The New York Times, by William Leonard Laurence

Mr. Laurence, science writer for The New York Times and a Pulitzer Prize winner, is a special consultant to the Manhattan Engineer District, the War Department's special service that developed the atomic bomb.

WITH THE ATOMIC BOMB MISSION TO JAPAN, Aug. 9 (Delayed)-We are on our way to bomb the mainland of Japan. Our flying contingent consists of three specially designed B-29 "Superforts," and two of these carry no bombs. But our lead plane is on its way with another atomic bomb, the second in three days, concentrating in its active substance an explosive energy equivalent to 20,000 and, under favorable conditions, 40,000 tons of TNT.

We have several chosen targets. One of these is the great industrial and shipping center of Nagasaki, on the western shore of Kyushu, one of the main islands of the Japanese homeland.

I watched the assembly of this man-made meteor during the past two days, and was among the small group of scientists and Army and Navy representatives privileged to be present at the ritual of its loading in the "Superfort" last night, against a background of threatening black skies torn open at intervals by great lightning flashes.

It is a thing of beauty to behold, this "gadget." In its design went millions of man-hours of what is without doubt the most concentrated intellectual effort in history. Never before had so much brainpower been focused on a single problem.

This atomic bomb is different from the bomb used three days ago with such devastating results on Hiroshima.

I saw the atomic substance before it was placed inside the bomb. By itself it is not at all dangerous to handle. It is only under certain conditions, produced in the bomb assembly, that it can be made to yield up its energy, and even then it gives only a small fraction of its total contents—a fraction, however, large enough to produce the greatest explosion on earth. 

The briefing at midnight revealed the extreme care and the tremendous amount of preparation that had been made to take care of every detail of the mission, to make certain that the atomic bomb fully served the purpose for which it was intended. Each target in turn was shown in detailed maps and in aerial photographs. Every detail of the course was rehearsed—navigation, altitude, weather, where to land in emergencies. It came out that the Navy had submarines and rescue craft, known as Dumbos and Superdumbos, stationed at various strategic points in the vicinity of the targets, ready to rescue the fliers in case they were forced to bail out. 

The briefing period ended with a moving prayer by the chaplain. We then proceeded to the mess hall for the traditional early morning breakfast before departure on a bombing mission. 

A convoy of trucks took us to the supply building for the special equipment carried on combat missions. This included the "Mae West," a parachute, a lifeboat, an oxygen mask, a flak suit and a survival vest. We still had a few hours before take-off time, but we all went to the flying field and stood around in little groups or sat in jeeps talking rather casually about our mission to the Empire, as the Japanese home islands are known hereabouts. 

In command of our mission is Maj. Charles W. Seeney, 25, of 124 Hamilton Avenue, North Quincy, Mass. His flagship, carrying the atomic bomb; is named The Great Artiste, but the name does not appear on the body of the great silver ship, with its unusually long, four-bladed, orange-tipped propellers. Instead it carried the number 77, and someone remarks that it was "Red" Grange's winning number on the gridiron. 

Major Seeney's co-pilot is First Lieut. Charles D. Albury, 24, of 252 Northwest Fourth Street, Miami, Fla. The bombardier, upon whose shoulders rests the responsibility of depositing the atomic bomb square on its target, is Capt. Kermit K. Beahan of 1004 Telephone Road, Houston, Tex., who is celebrating his twenty-seventh birthday today.

Captain Beahan has the awards of the Distinguished Flying Cross, the Air Medal and one Silver Oak Leaf Cluster, the Purple Heart, the Western Hemisphere Ribbon, the European Theatre Ribbon and two battle stars. He participated in the first Eighth Air Force heavy bombardment mission against the Germans from England on Aug. 17, 1942, and was on the plane that transported Gen. Dwight D. Eisenhower from Gibraltar to Oran at the beginning of the North African invasion. He has had a number of hair-raising escapes in combat. 

The navigator on The Great Artiste is Capt. James F. Van Pelt Jr., 27, of Oak Hill, W. Va. The flight engineer is M/Sgt. John D. Kuharek, 32, of 1054 Twenty-second Avenue, Columbus, Neb.; S/Sgt. Albert T. De Hart of Plainview, Tex., who celebrated his thirtieth birthday yesterday, is the tail gunner; the radar operator is S/Sgt. Edward K. Buckley, 32, of 529 East Washington Street, Lisbon, Ohio. The radio operator is Sgt. Abe M. Spitzer, 33, of 655 Pelham Parkway, North Bronx, N. Y.; Sgt. Raymond Gallagher, 23, of 572 South Mozart Street, Chicago, is assistant flight engineer. 

The lead ship is also carrying a group of scientific personnel, headed by Comdr. Frederick L. Ashworth, USN, one of the leaders in the development of the bomb. The group includes Lieut. Jacob Beser, 24, of Baltimore, Md., an expert on airborne radar. 

The other two Superfortresses in our formation are instrument planes, carrying special apparatus to measure the power of the bomb at the time or explosion, high speed cameras and other photographic equipment. 

Our "Superfort" is the second in line. Its commander is Capt. Frederick C. Bock, 27, of 300 West Washington Street, Greenville, Mich. Its other officers are Second Lieut. Hugh C. Ferguson, 21, of 247 Windermere Avenue, Highland Park, Mich., pilot; Second Lieut. Leonard A. Godfrey, 24, of 72 Lincoln Street, Greenfield, Mass., navigator; and First Lieut. Charles Levy, 26, of 1954 Spencer Street, Philadelphia, bombardier. 

The enlisted personnel of this "Superfort" are: T/Sgt. Roderick F. Arnold, 28, of 130 South Street, Rochester, Mich., flight engineer; Sgt. Ralph D. Curry, 20, of 1101 South Second Avenue, Hoopeston, Ill., radio operator; Sgt. William 6. Barney, 22, of Columbia City, Ind., radar operator; Corp. Robert J. Stock, 21, of 415 Downing Street, Fort Wayne, Ind., assistant flight engineer, and Corp. Ralph D. Belanger, 19, of Thendara, N. Y., tail gunner. 

The scientific personnel of our "Superfort" includes S/Sgt. Walter Goodman, 22, of 1956 Seventy-fourth Street, Brooklyn, N. Y., and Lawrence Johnson, graduate student at the University of California, whose home is at Hollywood, Calif. 

The third "Superfort" is commanded by Maj. James Hopkins, 1311 North Queen Street, Palestine, Tex. His officers are Second Lieut. John E. Caution, 516 North Takima Street, Tacoma, Wash., pilot; Second Lieut. Stanley C. Steinke, 604 West Chestnut Street, West Chester, Pa., navigator; and Second Lieut. Myron Faryna, 16 Elgin Street, Rochester, N. Y., bombardier. 

The crew are Tech. Sgt. George L. Brabenec, 9717 South Lawndale Avenue, Evergreen, Ill.; Sgt. Francis X. Dolan, 30-60 Warren Street, Elmhurst, Queens, N. Y.; Corp. Richard F. Cannon, 160 Cannel Road, Buffalo, N. Y.; Corp. Martin G. Murray, 7356 Dexter Street, Detroit, Mich., and Corp. Sidney J., Bellamy, 529 Johnston Avenue, Trenton, N. J. 

On this "Superfort" are also two distinguished observers from Britain, whose scientists played an important role in the development of the atomic bomb. One of these is Group Capt. G. Leonard Cheshire, famous Royal Air Force pilot, who is now a member of the British military mission to the United States. The other is Dr. William G. Denny, Professor of Applied Mathematics, London University, one of the group of eminent British scientists that has been working at the "Y-Site" near Santa Fe, N. M., on the enormous problems involved in taming the atom. 

Group Captain Cheshire, whose rank is the equivalent to that of colonel in the United States Army Air Forces, was designated as an observer of the atomic bomb in action by Winston Churchill when he was still Prime Minister. He is now the official representative of Prime Minister Clement R. Attlee. 

We took off at 3:50 this morning and headed northwest on a straight line for the Empire. The night was cloudy and threatening, with only a few stars here and there breaking through the overcast. The weather report had predicted storms ahead part of the way but clear sailing for the final and climactic stages of our odyssey. 

We were about an hour away from our base when the storm broke. Our great ship took some heavy dips through the abysmal darkness around us but it took these dips much more gracefully than a large commercial airliner, producing a sensation more in the nature of a glide than a "bump," like a great ocean liner riding the waves, except that in this case the air waves were much higher and the rhythmic tempo of the glide much faster. 

I noticed a strange eerie light coming through the window high above the navigator's cabin and as I peered through the dark all around us I saw a startling phenomenon. The whirling giant propellers had somehow became great luminous disks of blue flame. The same luminous blue flame appeared on the plexiglass windows in the nose of the ship, and on the tips of the giant wings it looked as though we were riding the whirlwind through space on a chariot of blue fire. 

It was, I surmised, a surcharge of static electricity that had accumulated on the tips of the propellers and on the di-electric material in the plastic windows. One's thoughts dwelt anxiously on the precious cargo in the invisible ship ahead of us. Was there any likelihood of danger that this heavy electric tension in the atmosphere all about us might set it off? 

I expressed my fears to Captain Bock, who seems nonchalant and imperturbed at the controls. He quickly reassures me: "It is a familiar phenomenon seen often on ships. I have seen it many times on bombing missions. It is known as St. Elmo's Fire." 

On we went through the night. We soon rode out the storm and our ship was once again sailing on a smooth course straight ahead, on a direct line to the Empire. Our altimeter showed that we were traveling through space at a height of 17,000 feet. The thermometer registered an outside temperature of 33 degrees below zero centigrade, about 30 below Fahrenheit. Inside our pressurized cabin the temperature was that of a comfortable air-conditioned room, and a pressure corresponding to an altitude of 8,000 feet. Captain Bock cautioned me, however, to keep my oxygen mask handy in case of emergency. This, he explained, might mean either something going wrong with the pressure equipment inside the ship or a hole through the cabin by flak. 

The first signs of dawn came shortly after 5 o'clock. Sergeant Curry, who had been listening steadily on his earphones for radio reports, while maintaining a strict radio silence himself, greeted it by rising to his feet and gazing out the window. 

"It's good to see the day," he told me. "I get a feeling of claustrophobia hemmed in in this cabin at night." 

He is a typical American youth, looking even younger than his 20 years. It takes no mind-reader to read his thoughts. 

"It's a long way from Hoopeston, Ill.," I find myself remarking. 

"Yep," he replies, as he busies himself decoding a message from outer space. 

"Think this atomic bomb will end the war?" he asks hopefully. 

"There is a very good chance that this one may do the trick," I assure him, "but if not, then the next one or two surely will. Its power is such that no nation can stand up against it very long." 

This was not my own view. I had heard it expressed all around a few hours earlier, before we took off. To anyone who had seen this man-made fireball in action, as I had less than a month ago in the desert of New Mexico, this view did not sound overoptimistic. 

By 5:50 it was real light outside. We had lost our lead ship, but Lieutenant Godfrey, our navigator, informs me that we had arranged for that contingency. We have an assembly point in the sky above the little island of Yakoshima, southeast of Kyushu, at 9:10. We are to circle there and wait for the rest of our formation. 

Our genial bombardier, Lieutenant Levy, comes over to invite me to take his front-row seat in the transparent nose of the ship and I accept eagerly. From that vantage point in space, 17,000 feet above the Pacific, one gets a view of hundreds of miles on all sides, horizontally and vertically. At that height the vast ocean below and the sky above seem to merge into one great sphere. 

I was on the inside of that firmament, riding above the giant mountains of white cumulous clouds, letting myself be suspended in infinite space. One hears the whirl of the motors behind one, but it soon becomes insignificant against the immensity all around and is before long swallowed by it. There comes a point where space also swallows time and one lives through eternal moments filled with an oppressive loneliness, as though ill life had suddenly vanished from the earth and you are the only one left, a lone survivor traveling endlessly through interplanetary space. 

My mind soon returns to the mission I am on. Somewhere beyond these vast mountains of white clouds ahead of me there lies Japan, the land of our enemy. In about four hours from now one of its cities, making weapons of war for use against us, will be wiped off the map by the greatest weapon ever made by man. In one-tenth of a millionth of a second, a fraction of time immeasurable by any clock, a whirlwind from the skies will pulverize thousands of its buildings and tens of thousands of its inhabitants. 

Our weather planes ahead of us are on their way to find out where the wind blows. Half an hour before target time we will know what the winds have decided. 

Does one feel any pity or compassion for the poor devils about to die? Not when one thinks of Pearl Harbor and of the Death March on Bataan. 

Captain Bock informs me that we are about to start our climb to bombing altitude. 

He manipulates a few knobs on his control panel to the right of him and I alternately watch the white clouds and ocean below me and the altimeter on the bombardier's panel. We reached our altitude at 9 o'clock. We were then over Japanese waters, close to their mainland. Lieutenant Godfrey motioned to me to look through his radar scope. Before me was the outline of our assembly point. We shall soon meet our lead ship and proceed to the final stage of our journey. 

We reached Yakoshima at 9:12 and there, about 4,000 feet ahead of us, was The Great Artiste with its precious load. I saw Lieutenant Godfrey and Sergeant Curry strap on their parachutes and I decided to do likewise. We started circling. We saw little towns on the coastline, heedless of our presence. We kept on circling, waiting for the third ship in our formation. 

It was 9:56 when we began heading for the coastline. Our weather scouts had sent us code messages, deciphered by Sergeant Curry, informing us that both the primary target as well as the secondary were clearly visible. 

The winds of destiny seemed to favor certain Japanese cities that must remain nameless. We circled about them again and again and found no opening in the thick umbrella of clouds that covered them. Destiny chose Nagasaki as the ultimate target. 

We had been circling for some time when we noticed black puffs of smoke coming through the white clouds directly at us. There were fifteen bursts of flak in rapid succession, all too low. Captain Bock changed his course. There soon followed eight more bursts of flak, right up to our altitude, but by this time were too far to the left. 

We flew southward down the channel and at 11:33 crossed the coastline and headed straight for Nagasaki about 100 miles to the west. Here again we circled until we found an opening in the clouds. It was 12:01 and the goal of our mission had arrived. 

We heard the prearranged signal on our radio, put on our arc-welder's glasses and watched tensely the maneuverings of the strike ship about half a mile in front of us. 

"There she goes!" someone said. 

Out of the belly of The Great Artiste what looked like a black object went downward. 

Captain Bock swung around to get out of range; but even though we were turning away in the opposite direction, and despite the fact that it was broad daylight in our cabin, all of us became aware of a giant flash that broke through the dark barrier of our arc-welder's lenses and flooded our cabin with intense light. 

We removed our glasses after the first flash, but the light still lingered on, a bluish-green light that illuminated the entire sky all around. A tremendous blast wave struck our ship and made it tremble from nose to tail. This was followed by four more blasts in rapid succession, each resounding like the boom of cannon fire hitting our plane from all directions. Observers in the tail of our ship saw a giant ball of fire rise as though from the bowels of the earth, belching forth enormous white smoke rings. Next they saw a giant pillar of purple fire, 10,000 feet high, shooting skyward with enormous speed. 

By the time our ship had made another turn in the direction of the atomic explosion the pillar of purple fire had reached the level of our altitude. Only about forty-five seconds had passed. Awestruck, we watched it shoot upward like a meteor coming from the earth instead of from outer space, becoming ever more alive as it climbed skyward through the white clouds. It was no longer smoke, or dust, or even a cloud of fire, It was a living thing, a new species of being, born right before our incredulous eyes. 

At one stage of its evolution, covering millions of years in terms of seconds, the entity assumed the form of a giant square totem pole, with its base about three miles long, tapering off to about a mile at the top. Its bottom was brown, its center was amber, its top white. But it was a living totem pole, carved with many grotesque masks grimacing at the earth. 

Then, just when it appeared as though the thing has settled down into a state of permanence, there came shooting out of the top a giant mushroom that increased the height of the pillar to a total of 45,000 feet. The mushroom top was even more alive than the pillar, seething and boiling in a white fury of creamy foam, sizzling upward and then descending earthward, a thousand Old Faithful geysers rolled into one. 

It kept struggling in an elemental fury, like a creature in the act of breaking the bonds that held it down. In a few seconds it had freed itself from its gigantic stem and floated upward with tremendous speed, its momentum carrying into the stratosphere to a height of about 60,000 feet. 

But no sooner did this happen when another mushroom, smaller in size than the first one, began emerging out of the pillar. It was as though the decapitated monster was growing a new head. 

As the first mushroom floated off into the blue it changed its shape into a, flowerlike form, its giant petal curving downward, creamy white outside, rose-colored inside. It still retained that shape when we last gazed at it from a distance of about 200 miles. 

ATOMIC BOMB RANGE, New Mexico, Sept. 9 (Delayed)-This historic ground in New Mexico, scene of the first atomic explosion on earth and cradle of a new era in civilization, gave the most effective answer today to Japanese propaganda that radiations were responsible for deaths even after the day of the explosion, Aug. 6, and that persons entering Hiroshima had contracted mysterious maladies due to persistent radioactivity.

To give the lie to these claims, the Army opened the closely guarded gates of this area for the first time to a group of newspapermen and photographers to witness for themselves the readings on radiation meters carried by a group of radiologists, and to listen to the expert testimony of several of the leading scientists who had been intimately connected with the atomic bomb project.

The ground, visited for the first time ever by Gen. Leslie R. Groves, over-all director of the atomic project, since that historic morning of Monday, July 16, gave awesome testimony on a number of subjects.

It revealed, even at a glance, the tremendous power of the atomic explosion that had blasted the earth over a radius of 800 yards from the center. 

It gave mute testimony of the enormous temperatures developed at the split instant of the explo-sion, fusing the earth for a radius of 1,200 feet into a green, glass-like coating resembling fine jade. 

It told of the enormous pressure that had compressed the earth below it over an area of 400 yards into a giant bowl that reached a depth of twenty-five feet. 

It showed that by far the majority of deaths within the radius of the explosion's effectiveness had been caused by the tremendous power of the blast and by the heat, and fires resulting from the temperatures, estimated at millions of degrees. 

The visitors saw a scene of desolation and devastation that made the surrounding semi-desert appear as a fertile oasis. Both from the ground and from the air, the sight is an unforgettable one. 

Before entering the area white canvas sandals to pull over our shoes were furnished to us. This, General Groves explained, was to make certain that some of the radioactive material still present in the ground might not stick to our soles. 

As we walked over the ground we were preceded by radiologists carrying Geiger counters; sensitive instruments that respond instantly to any radiation in their vicinity, revealing on a graduated dial the exact quantity present. 

The Geiger counters supplemented the testimony given by the ground's appearance. They showed that less than two months after the explosion the radiations on the surface had dwindled to a minute quantity, safe for continuous human habitation. 

Only in the center of the saucer, over a radius of about fifty yards, were the radiations higher than the standard tolerance dose for continuous exposure. In this area it would take 600 hours of continuous  habitation to produce fatal results, according to the scientists present. 

Furthermore, it was pointed out that the radioactive material on the fused surface constituted only about one-eighth of an inch. It would therefore be relatively easy to remove this surface material and make the ground safe for immediate habitation. 

At the rate the radiations have diminished during the past two months, it was pointed out, the entire area will be free of them within a relatively short time. 

The atomic explosion in New Mexico was from a steel tower only 100 feet from the ground, whereas the bombs over Hiroshima and Nagasaki were dropped from a bomber and exploded in the air from a much greater height, a scientist pointed out. Detonation at that height over the Japanese cities, he said, greatly reduced the absorption of the gamma rays in the ground, so that there were fewer of these radiations in Japan than in New Mexico.

This finding is bode out by a report just received by General Groves from Brig. Gen. Thomas F. Farrell, his next in command, who is now in Japan with a group of American scientists to study the effects of the bombs on the scene. 

The studies of the American scientists are still in the preliminary stage, General Groves stated. But he added that, according to General Farrell, Japanese sources now admitted that eleven days after the bomb had pulverized Hiroshima the radiation there was much less than the tolerance dose, which means, he added, that "you could live there forever." 

Most of the casualties in Hiroshima, these Japanese sources now admit, according to General Farrell, were owing to the blast and its consequent collapse of buildings and flying debris and to burns from radiant heat and subsequent fires. 

By far the majority of the deaths came from the blast, they believe. Persons in the center of the explosion, General Groves stated, "could be killed by fifteen different ways," but all the evidence indicates that it was the blast. The same Japanese sources now believe that there is no present danger in Hiroshima from surface radiations. Vegetation growing on the Hiroshima parade grounds supports this belief. 

"The Japanese claim," General Roves added, "that people died from radiations. If this is true, the number was very small."

"However, any deaths from gamma rays were due to those emitted during the explosion, not to the radiations present afterward. In the area where people could be killed by radiation they were killed by other causes, particularly blast. 

"While many people were killed, many lives were saved, particularly American lives. It ended the war sooner. It was the final punch that knocked them out. Otherwise they might have kept on fighting for a longer period." 

The Japanese are still continuing their propaganda aimed at creating the impression that we won the war unfairly, and thus attempting to create sympathy for themselves and milder terms, an examination of their present statements reveals. Thus, at the beginning, the Japanese described "symptoms" that did not ring true. More recently they have sent in a radiologist, and since then the symptoms they describe appear to be more authentic on the surface, according to the radiologists present here today. 

The Japanese, for example, had sent out a report that relief workers sent into Hiroshima after the blast had received radiation burns. 

"We now know from Japanese sources," General Groves went on, "that these were actually workers who were sent into Hiroshima before the bombing to evacuate the city on prior order. They simply were hurt in the original blast and were not examined and treated as they should have been." 

In addition to General Groves who represented the United States Army, the group of experts conducting the tour included Prof. J. R. Oppenheimer, who directed the scientific research and development of the bomb; Prof. Kenneth T. Bainbridge of Harvard University, who was in charge of the historic test explosion that gave the go-ahead signal for the atomic bombings of Hiroshima and Nagasaki; Dr. Victor R. Weisskopf, theoretical physicist of the University of Rochester (N. Y.); Prof. Robert F. Baeher of Cornell University, Dr. Richard W. Dodson, radiochemist of Pasadena, Calif.; Dr. Louis H. Hempelmann, radiologist of St. Louis, Mo.; Dr. J. G. Hoffman of Buffalo, and Major John Ferry, radiologist, of Oak Ridge, Tenn. 

Following is the first of a number of articles by a staff member of The New York Times who was detached for service with the War Department at its request to explain the atomic bomb to the lay public. He witnessed the first test of the bomb in New Mexico and, on a flight to Nagasaki, its actual use.

The Atomic Age began at exactly 5:30 Mountain War Time on the morning of July 16, 1945, on a stretch of semi-desert land about fifty airline miles from Alamagordo, N. M., just a few minutes before the dawn of a new day on this earth.

At that great moment in history, ranking with the moment in the long ago when man first put fire to work for him and started on his march to civilization, the vast energy locked within the hearts of the atoms of matter was released for the first time in a burst of flame such as had never before been seen on this planet, illuminating earth and sky for a brief span that seemed eternal with the light of many super-suns.

The elemental flame, first fire ever made on earth that did not have its origin in the sun, came from the explosion of the first atomic bomb. It was a full-dress rehearsal preparatory to use of the bomb over Hiroshima and Nagasaki—and other Japanese military targets had Japan refused to accept the Potsdam Declaration for her surrender.

The rehearsal marked the climax in the penultimate act of one of the greatest dramas in our history and the history of civilized man—a drama in which our scientists, with the Army Corps of Engineers as director, were working against time to create an atomic bomb ahead of our German enemy.

The collapse of Germany marked the end of the first act of this drama. The successful completion of our task, in the greatest challenge by man against nature so far, brought down the curtain on the second act. 

The grand finale came three weeks afterward over the skies of Japan with a swift descent of the curtain on the greatest war in history. The atomic flash in New Mexico came as a great affirmation to the prodigious labors of our scientists during the past four years, in which they managed to "know the unknowable and unscrew the inscrutable."

It came as the affirmative answer to the until then unanswered question: "Will it work?"

With the flash came a delayed roll of mighty thunder, heard, just as the flash was seen, for hundreds of miles. The roar echoed and reverberated from the distant hills and the Sierra Oscuro Range near by, sounding as though it came from some supramundane source as well as from the bowels of the earth. 

The hills said "yes" and the mountains chimed in "yes." It was as if the earth had spoken and the suddenly iridescent clouds and sky had joined in one mighty affirmative answer. Atomic energy—yes. 

It was like the grand finale of a mighty symphony of the elements, fascinating and terrifying, uplifting and crushing, ominous, devastating, full of great promise and great forebodings. 

I watched the birth of the Era of Atomic Power from the slope of a hill in the desert land of New Mexico, on the northwestern corner of the Alamogordo Air Base, about 125 miles southwest of Albuquerque. The hill, named Compania Hill for the occasion, was twenty miles to the northwest of Zero, the codename given to the spot chosen for lighting the first atomic fire on this planet. The area embracing Zero and Compania Hill, twenty-four miles long and eighteen miles wide, had the code name Trinity. 

I joined a caravan of three buses, three automobiles and a truck carrying radio equipment at 11 P. M. Sunday, July 15, at Albuquerque. There were about ninety of us in that strange caravan, traveling silently and in utmost secrecy through the night on probably as unusual an adventure as any in our day. 

With the exception of your correspondent, the caravan consisted of scientists from the highly secret atomic bomb research and development center in the mesas and canyons of New Mexico, twenty-five miles northwest of Santa Fe, where we solved the secret of translating the fabulous energy of the atom into the mightiest weapon ever made by man. It was from there that the caravan set out at 5:30 that Sunday afternoon for its destination, 212 miles to the south. 

These were the "mesa-men" on the march, dwellers in the "caves" in the interior of atoms, pioneer explorers of vast new continents in hitherto forbidden realms of the cosmos, builders of the civilization of tomorrow. 

Here on trails hallowed by pioneers of other days, who opened new frontiers and did not rest until they conquered a continent, "covered wagons" were rolling again through the night on their way to open still newer frontiers of a continent that has no limits in space. 

The caravan wound its way slowly over the tortuous roads overlooking the precipitous canyons of northern New Mexico, passing through Espagnola, Santa Fe and Bernadillo, arriving at Albuquerque at about 10 P. M. Here it was joined by Sir James Chadwick, who won the Nobel Prize and knighthood for his discovery of the neutron, the key that unlocks the atom; Professor Ernest O. Lawrence of the University of California, master atom-smasher, who won the Nobel Prize for his discovery of the cyclotron; Professor Edwin H. McMillan, also of the University of California, one of the discoverers of plutonium, the new atomic energy element, and several others from the atomic bomb center, who, with your correspondent, had arrived during the afternoon. 

The night was dark with black clouds and not a star could be seen. Occasionally a bolt of lightning would rend the sky and reveal for an instant the flat semi-desert landscape, rich with historic lore of past adventure. We, too, were headed for adventure, Argonauts on the way to a Golden Fleece richer by far than Jason ever found. We were on the road to the fabled golden Seven Cities of Cibola, sought in vain by Coronado on trails not too far away from the area we were traversing. 

We rolled along on U. S. Highway 85, running between Albuquerque and El Paso, through sleeping ancient Spanish-American towns, their windows dark, their streets deserted—towns with music in their names, Las Lunas, Belen, Bernardo, Alamillo, Socorro, San Antonio. 

At San Antonio we turned east and crossed "the bridge on the Rio Grande with the detour in the middle of it." We traveled ten and one-half miles eastward on U. S. Highway 380, where we turned south on a specially built dirt road, running for twenty-five miles to the Base Camp at Trinity. 

The end of our trail was reached after we had covered about five and one-fifth miles on the dirt road. Here we saw the first signs of life since we had left Albuquerque about three hours earlier, a line of silent men dressed in helmets. A little further ahead a detachment of military police examined our special credentials. 

We descended and looked about us. The night was still pitch black save for an occasional flash of lightning in the eastern sky, outlining for a brief instant the range of Sierra Oscuro directly ahead of us. We were in the middle of the New Mexico desert, miles away from nowhere, not a sign of life, not even a blinking light on the distant horizon. This was to be our caravansary until the zero hour. 

From a distance to the southeast the beam of a searchlight probed the clouds. This gave us our first sense of orientation. The bombing test site, Zero, was a little to the left of the searchlight beam, twenty miles away. With the darkness and the waiting in the chill of the desert the tension became almost unendurable. 

We gathered around in a circle to listen to directions on what we were to do at the time of the "shot," directions read aloud by the light of a flashlight: 

At a short signal of the siren at minus five minutes to zero "all personnel whose duties did not specifically require otherwise" were to prepare "a suitable place to lie down on." 

At a long signal of the siren at minus two minutes to zero "all personnel whose duties did not specifically require otherwise" were to "lie prone on the ground immediately, the face and eyes directed toward the ground and with the head away from Zero." 

"Do not watch for the flash directly," the directions read, "but turn over after it has occurred and watch the cloud. Stay on the ground until the blast wave has passed (two minutes). 

"At two short blasts of the siren, indicating the passing of all hazard from light and blast, all personnel will prepare to leave as soon as possible. 

"The hazard from blast is reduced by lying down on the ground in such a manner that flying rocks, glass and other objects do not intervene between the source of blast and the individual. Open all car windows. 

"The hazard from light injury to eyes is reduced by shielding the closed eyes with the bended arms and lying face down on the ground. If the first flash is viewed a 'blind spot' may prevent your seeing the rest of the show. 

"The hazard from ultraviolet light injuries to the skin is best overcome by wearing long trousers and shirts with long sleeves." 

David Dow, assistant to the scientific director of the Atomic Bomb Development Center, handed each of us a flat piece of colored glass used by arc welders to shield their eyes. Dr. Edward Teller of George Washington University cautioned us against sunburn. Someone produced sunburn lotion and passed it around. 

It looked eerie seeing a number of our highest ranking scientists seriously rubbing sunburn lotion on their faces and hands in the pitch blackness of the night, twenty miles away from the expected flash. These were the men who, more than anybody, knew the potentialities of atomic energy on the loose. It gave one an inkling of their confidence in their handiwork. 

The bomb was set on a structural steel tower 100 feet high. Nine miles away to the southwest was the base camp. This was G. H. Q. for the scientific high command, of which Professor Kenneth T. Bainbridge of Harvard University was field commander. 

Here were erected barracks to serve as living quarters for the scientists, a mess hall, a commissary, a Post Exchange and other buildings. Here the vanguard of the atomists, headed by Prof. J. R. Oppenheimer of the University of California, scientific director of the atomic bomb project, lived like soldiers at the front, supervising the enormously complicated details involved in the epoch-making tests. 

Here early that Sunday after-noon gathered Maj. Gen. Leslie R. Groves, Commander in Chief of the Atomic Bomb Project; Brig. Gen. T. F. Farrell, hero of World War I, General Groves' deputy; Prof. Enrico Fermi, Nobel Prize winner and one of the leaders in the project; President James Bryant Conant of Harvard; Dr. Vannevar Bush, Director of the Office of Scientific Research and Development; Dean Richard C. Tolman of the California Institute of Technology; Prof. R. F. Bacher of Cornell; Col. Stafford L. Warren, University of Rochester (N. Y.) radiologist, and a host of other leaders in the atomic bomb program. 

At the Base Camp was a dry, abandoned reservoir, about 500 feet square, surrounded by a mound of earth about eight feet high. Within this mound bulldozers dug a series of slit trenches, each about three feet deep, seven feet wide and about twenty-five feet long. At a command over the radio at zero minus one minute all observers at Base Camp, about 150 of the "Who's Who" in science and the armed forces, lay down "prone on the ground" in their pre-assigned trenches, "face and eyes directed toward the ground and with the head away from Zero." 

Three other posts had been es-tablished, south, north and west of Zero, each at a distance of 10,000 yards (5.7 miles). These were known, respectively, as South-10,000, North-10,000 and West-10,000, or 5-10, N-10 and W-10. 

Here the shelters were much more elaborate, wooden structures, their walls reinforced by cement, buried under a massive layer of earth. 

5-10 was the control center. Here Professor Oppenheimer, as scientific commander in chief, and his field commander, Professor Bainbridge, issued orders and synchronized the activities of the other sites. 

Here the signal was given and a complex of mechanisms was set in motion that resulted in the greatest burst of energy ever released by man on earth up till that time. 

No switch was pulled, no button pressed, to light this first cosmic fire on this planet. 

At forty-five seconds to zero, set for 5:30 o'clock, young. Dr. Joseph L. McKibben of the University of California, at a signal from Professor Bainbridge, activated a master robot that set off a series of other robots. Moving "electronic fingers" writ and moved on, until at last strategically spaced electrons moved to the proper place at the proper split second. 

The forty-five seconds passed and the moment was zero.

At our observation post on Compania Hill the atmosphere had grown tenser as the zero hour approached. We had spent the first part of our stay partaking of an early morning picnic breakfast that we had taken along with us. It had grown cold in the desert and many of us, lightly clad, shivered. Occasionally a drizzle came down and the intermittent flashes of lightning made us turn apprehensive glances toward Zero. 

We had had some disturbing reports that the test might be called off because of the weather. The radio we had brought along for communication with Base Camp kept going out of order, and when we had finally repaired it some blatant band would drown out the news we wanted to hear. 

We knew there were two specially equipped 3-29 Superfortresses high overhead to make observations and recordings in the upper atmosphere, but we could neither see nor hear them. We kept gazing through the blackness. 

Suddenly, at 5:29:50, as we stood huddled around our radio, we heard a voice ringing through the darkness, sounding as though it had come from above the clouds: 

"Zero minus ten seconds!" 

A green flare flashed out through the clouds, descended slowly, opened, grew dim and vanished into the darkness. The voice from the clouds boomed out again: "Zero minus three seconds!" 

Another green flare came down. Silence reigned over the desert. We kept moving in small groups in the direction of Zero. From the east came the first faint signs of dawn. 

And just at that instant there rose from the bowels of the earth a light not of this world, the light of many suns in one. 

It was a sunrise such as the world had never seen, a great green super-sun climbing in a fraction of a second to a height of more than 8,000 feet, rising ever higher until it touched the clouds, lighting up earth and sky all around with a dazzling luminosity. 

Up it went, a great ball of fire about a mile in diameter, changing colors as it kept shooting upward, from deep purple to orange, expanding, growing bigger, rising as it was expanding, an elemental force freed from its bonds after being chained for billions of years. 

For a fleeting instant the color was unearthly green, such as one sees only in the corona of the sun during a total eclipse. 

It was as though the earth had opened and the skies had split. One felt as though he had been privileged to witness the Birth of the World—to be present at the moment of Creation when the Lord said: Let There be Light. 

On that moment hung eternity. Time stood still. Space contracted into a pinpoint. 

To another observer, Prof. George B. Kistiakowsky of Harvard, the spectacle was "the nearest thing to Doomsday that one could possibly imagine." 

"I am sure," he said, "that at the end of the world—in the last millisecond of the earth's existence—the last man will see what we saw!" 

A great cloud rose from the ground and followed the trail of the Great Sun. 

At first it was a giant column that soon took the shape of a supramundane mushroom. For a fleeting instant it took the form of the Statue of Liberty magnified many times. 

Up it went, higher, higher, a giant mountain born in a few seconds instead of millions of years, quivering convulsively. 

It touched the multi-colored clouds, pushed its summit through them, kept rising until it reached a height of 41,000 feet, 12,000 feet higher than the earth's highest mountain. 

All through this very short but extremely long time-interval not a sound was heard. I could see the silhouettes of human forms motionless in little groups, like desert plants in the dark. 

The new-born mountain in the distance, a giant among pigmies against the background of the Sierra Oscuro range, stood leaning at an angle against the clouds, a vibrant volcano spouting fire to the sky. 

Then out of the great silence came a mighty thunder. For a brief interval the phenomena we had seen as light repeated themselves in terms of sound. 

It was the blast from thousands of blockbusters going off simultaneously at one spot. 

The thunder reverberated all through the desert, bounced back and forth from the Sierra Oscuros, echo upon echo. The ground trembled under our feet as in an earthquake. 

A wave of hot wind was felt by many of us just before the blast and warned us of its coming. 

The Big Boom came about 100 seconds after the Great Flash—the first cry of a newborn world. It brought the silent, motionless silhouettes to life, gave them a voice. 

A loud cry filled the air. The little groups that hitherto had stood rooted to the earth like desert plants broke into a dance, the rhythm of primitive man dancing at one of his fire festivals at the coming of spring. 

They clapped their hands as they leaped from the ground—earth-bound man symbolizing a new birth in freedom—the birth of a new force that for the first time gives man means to free himself from the gravitational pull of the earth that holds him down. 

The dance of the primitive man lasted but a few seconds, during which an evolutionary period of about 10,000 years had been telescoped. Primitive man was metamorphosed into modern man—shaking hands, slapping each other on the back, laughing like happy children.

The sun was just rising above the horizon as our caravan started on its way back to Albuquerque and Los Alamos. It rose to see a new thing under the sun, a new era in the life of man. 

We looked at it through our dark lenses to compare it with what we had seen. 

"The sun can't hold a candle to it!" one of us remarked. 

Following is the second of a number of articles by a staff member of The New York Times who was detached for service with the War Department at its request to explain the atomic bomb to the lay public. He witnessed the first test of the bomb in New Mexico and, on a flight to Nagasaki, its actual use. 

The great cloud of fire and smoke that rose more than eight miles to the stratosphere over the New Mexico desert on the morning of July 16, when the first atomic bomb poured out its energy in an explosive burst greater than any ever produced on earth, symbolized a funeral pyre for the Japanese Empire. 

The select few who witnessed the spectacle knew for certain at the instant of the explosion that the new weapon would prove decisive in a relatively short time. No power on earth, everyone realized, could stand up against the elemental force liberated in these bombs. 

That cosmic fire that lighted earth and sky for hundreds of miles was a modern version of the Biblical handwriting on the wall to the Japanese and all would-be future aggressors. Mene, Mene, Tekel, Upharsin. He has counted, counted, weighed and they divide. You have been weighed and found wanting. 

For the immediate future—and that was what everyone involved in the atomic bomb project was mostly concerned with at the time—that mightiest man-made thunderbolt meant life for many thousands of our fighting men. It meant a quicker end to the war, assurance of a speed-up in the coming of peace to the firesides of America and her Allies. 

The weeks preceding the test, when the scientists were putting the final touches on what they used to refer to as the "gadget," witnessed the most dramatic scenes in the history of scientific endeavor. Work went on feverishly day and night. The air was tense with the very energy of the atomic substance being prepared for the crucial test, the tests of tests. 

The very decision to make the test took many long hours of discussion of all the pros and cons involved. It was finally concluded that only an actual explosion of the atomic bomb under controlled conditions would reveal any possible hidden faults that could not otherwise be corrected were we to drop it untested on the enemy. 

The decision opened up a host of serious problems. A site had to be found far away from inhabited localities. Measures had to be taken to prevent the tremendous thunderbolt, which was expected to be seen and heard for hundreds of miles, from giving away our greatest secret. 

On the scientific side, the heart and purpose of the test, apparatus and techniques had to be devised to study, from a distance of several miles entirely by automatic controls, phenomena that take place in less than a millionth of a second. These included measurements of what takes place inside the atomic bomb at the time of explosion, the amounts and types of energy released, the effect, intensity and extent of the blast, the post-explosion radiations on the ground and in the air, meteorological observations and a host of other phenomena that took five typewritten pages to enumerate. 

The studies were devised to make the bomb tell its story before, during and after the detonation. For this purpose scores of the most delicate measuring, photographing and recording devices, old and new, were placed in concrete pillboxes and underground shelters over a radius of many miles. 

These included a number of high speed cameras of all types, numerous electronic devices, supersonic detectors, all sorts of instruments for probing inside the infinitesimal world of the atom's nucleus, devices to measure the intensity of the blast, radiation meters, and a host of other special equipment. 

It required about 500 miles of wiring to connect the various electrically operated instruments in the bomb-proof shelters several miles away to the site of the "gadget." Seismographs were also placed at various distances to measure the effects of the atomic explosion underground, and especially equipped B-29 Superfortresses went aloft to study the effects in the upper atmosphere.

More than 300 scientists were involved in the test, including a number of Nobel Prize whiners and scores of the world's leading physicists, chemists, radiologists, meteorologists, mathematicians and explosive and ballistics experts. About 250 military personnel were engaged in carrying out the security and protective measures. 

A providential warning that came a few days before the test led to hasty last-minute changes designed to prevent a possible catastrophe that had not been foreseen. A dummy bomb, an exact duplicate of the atomic "gadget," had been set up on the tower as a practice model. A thunderstorm came along and touched it off. 

This led to protective measures against the possibility that a bolt of lightning might set off the first atomic explosion on earth, possibly at a time when the scientists were still in its vicinity. 

The northwestern section of the 2,000 square-mile Alamogordo Air Base was chosen as the test-site because of its isolation, inaccessibility, desirable meteorological characteristics and its remoteness from large towns. Its nearest inhabited locality is the village of Carrizozo, population 1,500, about thirty airline miles due east from the spot selected for the first atomic explosion. 

Other communities in the locality are Socorro, population 3,500, about thirty miles to the northwest, and Alamogordo, fifty miles to the southeast. The nearest large city is Albuquerque, about 125 miles to the northwest. 

Everything relating to the "gadget," the spot where it stood on its tower, the time scheduled for its blow-off, as well as the "Great God It" of the occasion was referred to as "Zero," the code name for the site. 

For everyone concerned Zero became the center a the universe. Time and space began and ended at Zero. All life centered about Zero. Everyone thought only of Zero and the zero hour, or rather the zero-microsecond. 

The only living beings that dared venture near the spot where Zero vanished in a great cloud of atomic fire was a crew of scientists in two Sherman tanks, the insides of which were lined with lead. They took samples of the earth by means of special scoops manipulated from the inside and made preliminary observations of the site, which, later observations revealed, was depressed over a radius of 400 yards to a depth ranging from ten feet, at the periphery to twenty-five feet in the center. 

The transfer of the "gadget" over a distance of more than 200 miles from Los Alamos to Zero presented a major problem, involving both security and safety. The transportation of this precious stuff, possessing a value inestimable in terms of worldly considerations, was in charge of the Military Intelligence branch at Los Alamos, headed by Capt. Thomas O. Jones, formerly a Chicago lawyer. 

One of the historic moments came on Tuesday, July 3, when a group of young physicists, who had learned to tame the wildest elemental force in nature, brought the active material to the point they call "criticality," a point at which the atomic substance is brought as close as possible to the exploding stage. 

This was no mere game tempting fate. It had to be done to check theory with practice. 

Several units of the complicated assembly left Los Alamos Thursday morning, July 12, in a convoy accompanied by armed guards and several scientists, arriving at its destination that same afternoon. Another convoy left Los Alamos at 12:01 Friday morning, July 13, arriving at Zero nine hours later. 

Professor R. F. Bacher of Cornell and Professor George B. Kistiakowaky of Harvard were in charge of the assembly of the principal units of the "gadget." The assembly of the entire unit was completed on Saturday, July 14. Tests by the score were carried out to make certain that every part functioned properly. 

A week earlier a group of leading radiologists under the direction of Colonel Stafford L. Warren, of the  University. of Rochester (N. Y.), began setting up a network of radiological stations at various distances to measure the radiation effects of the explosion. The flash lighted up the sky at Albuquerque and was seen as far as Amarillo, Tex., 450 miles east of Zero. At El Paso 150 miles to the south, persons saw the flash and heard the blast and two successive echoes. Residents of Silver City, N. M., 200 miles to the southwest, and at Gallup, N. M., 235 miles to the northwest, reported that their windows rattled, those at Gallup stating that they also heard two explosions. 

Various reports from a number of other localities listed the explosion as an earthquake, a meteor, or an airplane crash. Members of the crew and passengers aboard a Santa Fe Railroad train near Mountainair, about seventy miles to the northeast, thought they saw a bomber explode and burn in the sky. 

A subsequent examination of the ground revealed that all life, vegetable as well as animal, was destroyed within a radius of about a mile. There was not a rattlesnake left in the region, nor a blade of grass. The sand within a radius of 400 yards was transformed into a glass-like substance the color of green jade. A steel rigging tower weighing thirty-two tons, at a distance of 800 yards, was turned into a twisted mass of wreckage. 

A herd of antelope that had been grazing several miles away vanished completely. Up to the present the antelope have not returned. 

To Prof. J. R. Oppenheimer of the University of California, who directed the work on the bomb, the effect, he told me, was "terrifying" and "not entirely undepressing." After a pause, he added:

"Lots of boys not grown up yet will owe their life to it!"

Atomic energy, harnessed for the first time by our scientists for use in atomic bombs, is the practically inexhaustible source of power that enables our sun to supply us with heat, light and other forms of radiant energy without which life on earth would not be possible.

It also is the same energy, stored in the nuclei of the atoms of the material universe, that keeps the stars, bodies much larger than our sun, radiating their enormous quantities of light and heat, for billions of years, instead of burning themselves out in periods measured only in thousands of years.

The existence of atomic energy first was discovered by Einstein about forty years ago on purely theoretical grounds, as an outgrowth of his famous relativity theory, according to which a body in motion has a greater mass than the same body at rest, this increase in motion bearing a direct relationship to the velocity of light. This meant that the energy of motion imparted an actual increase in mass.

From the formula for the relationship of this increase of mass to the velocity of light Einstein derived his famous mathematical equation that revealed for the first time an equivalence between mass and energy, one of the most revolutionary concepts in the intellectual history of mankind. The mass-energy equation showed that any given quantity of mass was the equivalent of a specific amount of energy, and vice versa.

Specifically this equation revealed the (at that time) incredible fact that very small amounts of matter contained tremendous amounts of energy. A piece of coal the size of a pea, the equation proved, contained enough energy to drive the largest ocean liner across the Atlantic and back. No one, however, least of all Einstein himself, believed at the time that any means ever could be found to tap this cosmic source of elemental energy.

In the mass-energy theorem, Einstein showed the existence of a definite relationship between the Cosmic Trinity of, matter, energy and the velocity of light. The relationship is so simple that, once arrived at, a grammar school student could work it out.

In this formula the letter "m" stands for mass in terms of grams; the letter "E" represents energy in terms of ergs (a small unit of energy or work); while the letter "c" stands for the velocity of light in terms of centimeters per second. The energy content of any given quantity of any substance, the formula states, is equal to the mass of the substance (in terms of grams), multiplied by the square of the velocity of light (in terms of centimeters per second). The velocity of light (in round numbers) is 300,000 kilometers, or 30,000,000,000 centimeters, per second.

Take one gram of any substance. According to the Einstein formula the amount of energy ("E") in ergs in this mass is equal to 1 (the mass of the substance in grams) multiplied by 30,000,000,000 squared. In other words, the en-ergy content of one gram of matter, equals 900 billion billion ergs. Translated in terms of pounds and kilowatt-hours this means that one pound of matter contains the energy equivalent of 10,000,000,000 kilowatt-hours.

If this energy could be fully utilized it would take only twenty-two pounds of matter to supply all the electrical power requirements of the United States for a year.

One-third of a gram of water would yield enough heat to turn 1,000 tons of water into steam.

One gram of water would raise a load of a million tons to the top of a mountain six miles high.

A breath of air would operate a powerful airplane continuously for a year.

A handful of snow would heat a large apartment house for a year.

The pasteboard in a small railroad ticket would run a heavy passenger train several times around the world.

A cup of water would supply the power of a great generating station of 100,000-kilowatt capacity for a year.

One pound of any substance, if its atomic energy content could be utilized 100 percent; is equivalent in power-content to 3,000,000,000 pounds of coal; or 1,500,000 tons. The energy we now are able to utilize in the atomic bombs, at maximum efficiency, constitutes only one-tenth of 1 percent of the total energy present in the material. But even one-hundredth of 1 percent still would be the most destructive force by far on this earth.

Atomic energy, released through the splitting of atoms, differs radically from ordinary types of energy hitherto available to mar in that it involves annihilation of matter. When an atom is split part of its matter is converted into energy.

This is materially different from obtaining power by the use of a water wheel, for example, or by the burning of coal or oil. In the case of the water wheel, the water molecules taking part remain entirely unchanged. They simply lose potential energy as they pass from the dam to the tailrace.

In the case of burning coal or oil a more intense process takes place, as the atoms of carbon, hydrogen and oxygen (of which the coal and oil molecules are composed) are regrouped by combustion into new molecules forming new substances. The atoms themselves, however, still remain unchanged—they still are carbon, hydrogen and oxygen. None of them, as far as can be measured, loses any part of its mass.

In the case of atomic energy, however, the atom itself completely changes its identity, and in this process of change it loses part of its mass, which is converted into energy. The amount of energy liberated in this process is directly proportional to the amount of atomic mass destroyed. The sun, for example, obtains its energy through the partial destruction of its hydrogen, through a complete process in which the hydrogen is converted into helium.

In this process, four hydrogen atoms, each with an atomic mass of 1.008 (total, 4.032 atomic mass units) combine to form one helium atom, which has an atomic mass of 4.003. This represents a loss of mass on the part of the four hydrogen atoms (in addition to a loss of two positive electrons) of 0.029 atomic mass units, which is converted into pure energy. The amount of energy liberated in this process by the enormous quantities of hydrogen in the sun represents an actual loss of the sun's mass at the rate of 4,000,000 tons per second, a mere speck of. dust in. relation to the sun's total mass of two billion billion billion tons.

If the sun, however, were a mass of coal weighing the same amount, it would have to burn 3,000,000,000 times the mass it is burning now to produce the same amount of energy. If that were the case it would have used up the entire store of molecular energy contained in its body of coal in the course of 5,750 years. In other words, it would have burned out long before the earth was born.

By the use of atomic energy, the sun has been able to give off its enormous amounts of radiation for a period estimated at 10,000,000,000 years, and its mass, at the present rate of burning, is enough to last 15,000 billion years more, although, of course, the amount of its radiation would .be greatly re-duced long before that in proportion to the decrease of its mass. Radiations in amounts sufficient to support life on earth are estimated to continue for some 10,000,000,000 to 100,000,000,000 years longer.

Since the very existence of atomic energy was first discovered through the theory of relativity, the development of the atomic bomb constitutes the most dramatic proof so far offered for the correctness of the theory, and also marks the first time it has been put to practical use in mundane affairs.

It is one of the great ironies of history that the German war lords, who drove Einstein into exile, were forced to rely on the theory of relativity in their efforts to develop an atomic bomb to save them from defeat. America, of which Einstein now is an honored citizen, succeeded where the Nazis failed. When the bombs fell over Hiroshima and Nagasaki they represented the fruition of what had been originally a pure mathematical concept.

Had that concept not come when it did, the development, of the atomic bomb also might have had to wait. This might have meant a prolongation of the war.

Thousands of young Americans this May owe their lives to the theory of relativity. Which is another way of saying that pure science, no matter how impractical it may appear, pays high dividends in the end.

Those few who, like your correspondent, had the rare privilege of visiting the research laboratories and the mammoth plants in which the work of mastering the atom is being carried on, first blink in amazement and find it difficult to believe the evidence of their senses.

This is true even of the leading scientists who have been intimately connected with the work from the beginning. They frankly admit that they still find themselves constantly amazed when they realize how the truth has outstripped fiction. Said President James Bryant Conant of Harvard, one of the leading advisers on the atomic bomb project: "They won't believe it when the time comes when this can be told. It is more fantastic than Jules Verne."

"They'll believe if it works," I replied. The visitor from the outside finds himself in a state of constant amazement, seeing one "impossible" after another materialize before him. He finds himself on a journey through a scientific vonderland. All around him are "such stuff as dreams are made on." To all intents he is a visitor on Mars.

The key to atomic energy was found in 1939, when it was discovered that uranium of atomic weight 235 (11-235), a rare form of the element, could be split and made to yield relatively enormous amounts of energy from the nucleus, or core, of its atoms. The amount of energy thus released is so great that one pound of U-235 is the equivalent of 3,000,000 pounds of coal, 2,000,000 pounds of gasoline or 20,000,000 pounds of TNT.

The catch was that the atoms of U-235, as found in nature, were inextricably mixed with the atoms of ordinary uranium of atomic weight 238 (U-238), the former constituting only seven-tenths of 1 per cent of the mixture. Since both forms of uranium are twins  (isotopes), possessing the same chemical properties, they cannot be separated by chemical means, while physical methods for its concentration were, from a practical point of view, non-existent, as it would have taken 1,000 of the then best pieces of apparatus 1,000 years to produce one ounce. 

But this "interplanetary" visitor found that in the course of three years our scientists and engineers had built an "Atomland-on-Mars," a scientific Never-Never Land, where the accepted "impossibles" of yesterday were transmuted, by the magic of imagination, concentrated brain-power and will-to-do, under the stimulus of a great national emergency, into actualities
of staggering dimensions.

If a Rip Van Winkle had gone to sleep shortly after the first flight of the Wright brothers in 1903 and then had awakened to gaze at a B-29 Superfortress he could not have been more surprised than the visitor to one of the mammoth plants where U-235 is being concentrated in relatively enormous amounts. 

Before the war the "amounts" of U-235 that had been concentrated for experimental purposes could not be seen even under the most powerful microscope. The largest "amount" then available weighed less than two-hundredths of a microgram, whereas a dime weighs 2,500,000 micrograms.

Most spectacular of all, our scientists and engineers have contrived, by the greatest miracle of modern alchemy, to create two entirely new elements, neptunium and plutonium, each heavier than uranium, neither of which had been known to exist in nature. Plutonium, occupying No. 94 on the Periodic Table of the Elements, yields atomic energy in amounts equal to uranium 235, the ninety-second and last of the elements found in nature.

Plutonium can be created out of ordinary uranium 238. This is of the utmost significance. For whereas U-235 constitutes only seven-tenths of 1 percent of nature's uranium supply, the development of means for transmuting the 99.3 percent of ordinary uranium into plutonium increases the source of atomic energy that can be tapped considerably more than a hundredfold.

There are mammoth plants in "Atomland-on-Mars," situated on a semi-desert site fifteen miles north-west of Pasco, Wash., where plutonium is being produced in relatively enormous quantities. The feeling one gets on visiting these plants is something akin to a strange awareness of the supernatural.

In these Promethean structures, that may well stand as eternal monuments to American genius and enterprise heralding the new Age of Atomic Power, as well as to the Spirit of Man Challenging Nature, mighty cosmic forces are at work such as had never been let loose on this planet in the million years of man's existence on its surface, and probably never in the two billion years of the earth's being.

Here, for the first time in history, man stands in the presence of the very act of elemental creation of matter. Here in the great silences—for the plants operate in a stillness where only the beating of one's heart can be heard—new elements are being born, a phenomenon that, as far as man knows, has not happened since Genesis.

This development no doubt will rank in the future story of mankind as a definite landmark; marking the ushering in of a new cultural age, the Age of Atomics, or the Age of Nucleonics, as some scientists prefer to designate it. For this there is no parallel in human history. All the great ages in man's past—the Iron Age, the Bronze Age, the ages of steam and electricity—each of which revolutionized man's life on this earth, entered the stage of history imperceptibly, and man did not become aware of then" until their effects were fully felt.

This marks the first time in the history of man's struggle to bend the forces of nature to his will that he actually is present at the birth of a new era on this planet, with full awareness of its titanic potentialities for good or evil.

In addition to the enormous work of producing U-235 and plutonium in the amounts required there also was the equally gigantic task of utilizing these elements—carrying the most concentrated explosive wallop of any substance on earth—into atomic bombs for bringing the war to the speediest possible end.

The design and construction of the bombs called for the concentration of the most powerful "beam" of collective intelligence ever brought to bear upon any single project. Some of the outstanding minds in this group, such as Prof. Enrico Fermi, Nobel Laureate, of Columbia University; Prof. Eugene Wigner of Princeton, Dr. Leo Szillard and Prof. H. A. Bethe of Cornell, came to us as exiles from Nazi and Fascist fury. One of them, Prof. Niels Bohr, Nobelist and one of the world's greatest scientists, was rescued from German-occupied Denmark in one of the most spectacular single feats of the war.

The site where the research and development laboratory for the bomb is located, at Los Alamos, N. M., was the topmost of all top secrets of the atomic bomb project. Hidden away in the mesas and canyons of New Mexico, twenty-five miles northwest of Santa Fe, overcooked by the majestic Sangre de Cristo mountains that at sunrise and at twilight give the appearance of mountains on fire, this spot is the most "Martian" of all places in "Atomland-on-Mars."

Here the unbelievable meets one everywhere. Here a new species of man, Mesa Man, is laying the foundation of the civilization of tomorrow, if there is to be a tomorrow.

For the power now utilized in a weapon for destruction could also, with the same application of brain-power, will-to-achieve and imagination, be developed for bringing man much nearer to mastery of his material universe. Man has it in his power at last to realize the dream of the ages, for he has found the veritable "Philosopher's Stone" sought in vain by the alchemists, a key to the fountainhead of the very power that keeps the universe going.

Here, among other things, man at last has a fuel powerful enough to free him from the gravitational bonds of the earth.

All existing fuels have only a little more than the energy needed to lift their own weight beyond the earth's gravitational field. Hence no rocket, or spaceship, hitherto could be made that would leave the earth, as no existing fuel has enough power to lift both its own weight as well as the weight of the rocket to a point from which they no longer would be pulled back.

In the atomic bomb, on the other hand, there is more than a million times the energy needed to get beyond the earth's field of gravity. This, therefore, opens the possibility for building a rocket to the moon, or Mars.

Man for the first time has the fuel for such a rocket. He stills lack the engine to utilize this "cosmic fire." While scientists point to enormous obstacles still to be overcome for the propulsion of such a rocket, they do not regard them as basically insurmountable.

The Interplanetary Era may not yet be around the corner, but it already is faintly discernible on the far-off horizon.

Following is the fifth of a number of articles by a staff member of The New York Times who was detached for service with the War Department at its request to explain the atomic bomb to the lay public. He witnessed the first test of the bomb in New Mexico and, on a flight to Nagasaki, its actual use.

When the discovery of the tremendous potentialities of uranium 235 (U-235) as a vast new source of atomic energy, and as a potential military weapon of enormous destructive powers, was made in 1939, it appeared first as a mirage, a sort of scientific fata morgana, whereby nature chose to tantalize man.

By what Professor Enrico Fermi described at the time as the "innate cussedness of nature," U-235 was found inextricably mixed with ordinary uranium (U-238), of which it constituted only seven-tenths of 1 percent. U-235 being as like U-238 as tweedledum to tweedledee, the two could not be separated except in sub-microscopic amounts.

There were so many completely unknown phases of the possible methods for producing U-235 that it was decided, in December, 1942, to proceed toward the construction of several major plants, each for the development of a special method of production. It was thought at the time that at least one of the methods would develop insurmountable difficulties that would necessitate its abandonment, and it was not considered wise to put all our eggs into one basket.

As it turned out, however, while, great difficulties were encountered they were all surmounted one by one, and no one method developed such a superiority over the others as to justify their abandonment.

One of these methods, known as the electromagnetic method, is based on the principle that electrically charged atoms (ions) describe a curved path as they move through a magnetic field. Atoms of different mass and the same electric charge, when moving with the same speed through the magnetic field, follow different circles, and the path of the heavier atoms has a longer radius than the path of the lighter atoms.

The atoms are most separated after traversing half of their respective circles, at which point they are collected in specially designed containers.

The pre-war apparatus for the separating of light from heavy atoms by the electromagnetic method was known as a mass spectrometer. It consisted of four principal parts: A source for the production and acceleration of Ions; collectors in which the separated ions are deposited; a large magnet to make the atoms follow a curved path, and a tube, chamber, or tank, pumped down to low pressure, in which the particles (ions) travel from the source to the collector.

The tank is placed between the pole faces of the magnet.

Solid or liquid compounds containing the atoms to be separated must first be vaporized by the application of heat. The ions to be separated are produced in the source by an electric arc running through the vapor.

They are then accelerated by a high voltage system and made to travel at constant speed along curved paths in the magnetic field. Upon arrival at the collectors the ions are neutralized, i.e. they give up their electric charge, and solid material is deposited.

A high vacuum must be maintained in the tank in which the ions travel to reduce the number of gas molecules present, as where the ions collide with gas molecule! they are deflected from their path resulting in less material being collected and greater contamination of the material.

The pre-war vintage of this apparatus consisted of a small magnet and a vacuum tube about three feet long. It would have required about 15,000,000 of them to produce at the rate of 2 pounds of U-235 a year.

This midget has been metamorphosed into a giant plant covering 500 acres. Instead of sub-microscopic amounts it turns out U-235 on a mass-production basis. Credit for this remarkable transmutation of a laboratory toy into a giant industrial plant in an incredibly short time is largely due to Professor Ernest O. Lawrence of the University of California, one of the world's outstanding experimental physicists, who won the Nobel Prize for his invention and development of the cyclotron, atomic "slingshot."

It was generally believed that the electromagnetic method had some serious limitations to make it practical for large-scale separation of U-235. Dr. Lawrence, however, was not convinced that the indicated limitations were insurmountable. In November, 1941, without any financial assistance from any government agency, he proceeded to rip his 37-inch cyclotron apart and put its 85-ton magnet to use lin a giant mass spectrometer.

Within three months he had produced a relatively enormous amount, which was thousands of times greater than had ever been concentrated before, and at a ten times faster rate. This quantity was sufficient to be useful in determining the properties of the material and to demonstrate that the electromagnetic method of separation held possibilities of ultimate success.

During the course of this preliminary work the Research Corporation made a grant of $5,000 to the University of California Radiation Laboratory, directed by Dr. Lawrence, In December, 1941, the National Defense Research Committee, headed by President James Bryant Conant of Harvard, offered a Government contract to underwrite this phase of the research, and the grant from the Research Corporation was returned.

After the preparation of the first sample, experiments were pushed day and night to increase the output of the equipment. By March, 1942, alterations had raised the production rate for short periods by a factor of 500.

By May 26, 1942, the great 184-inch magnet, largest of its kind in the world, was turned on for the first time on the concentration of U-235. Its completion as the world's largest cyclotron had been indefinitely postponed some months previously in favor of its 7 conversion into a giant mass spectrometer, the greatest by far ever built. The Rockefeller Foundation made a grant of $60,000 for the conversion, as a contribution to the Radiation Laboratory's war research. This giant showed by mid-summer of 1942 that the electromagnetic method was practical, and that a large enough electromagnetic plant could have a critical; bearing on the war and inestimable implications for the future.

By the fall of 1942 plans for a small pilot plant to be built at Berkeley, Calif., were approved. It soon became apparent, however, that time would not permit this conventional intermediary development between laboratory and production plant. Plans for the pilot plant were therefore abandoned and all efforts reoriented toward the single purpose of building a large industrial plant and putting it in operation in the shortest possible time.

Since the plant was to require a tremendous amount of electric power, it was decided to locate it in the Tennessee Valley on the 59,000-acre Government reservation, eighteen miles northwest of Knoxville. Stone & Webster was selected to design and build the plant. General Electric, Westinghouse and Allis-Chalmers were the major suppliers of equipment. The Tennessee Eastman Corporation was picked to operate the plant.

These companies established offices at the University of California Radiation Laboratory early in 1943. Their scientists and engineers worked in the closest conjunction with the laboratory's physicists, chemists, engineers and shop technicians to translate data, procedures, techniques and equipment into a practical functioning plant design.

Tests of the mechanical and electrical equipment for the plant's installations were carried on at the Radiation Laboratory simultaneously with the construction of the plant buildings at the Clinton Engineer Works in Tennessee.

The results of these tests suggested many modifications of equipment to give smoother plant operation and increased output. 

Construction of the plant began Feb. 3, 1943, and the first units were placed in operation Jan. 27, 1944. It has hundreds of buildings of a permanent nature. Its operating personnel totals more than 20,000.

Building the Tennessee plant involved problems of construction and design never encountered before, since it is the first and only one of its kind in the world, and there was no time even to construct a small pilot plant that could have served as a model.

Since the electrified atoms to be separated must travel in a very high vacuum, high-speed vacuum pumps such as never existed be-fore had to be created. After much research Distillation Products Company developed pumps that produce and maintain extremely low atmospheric pressures. No vacuum pumps capable of operating at such high speeds and such low pressures are commercially in use in any other process.

Great difficulties also had to be overcome in designing extremely delicate control equipment for high voltage current. Rectifier units had to be designed capable of supplying a certain amperage at a very high voltage. These requirements are far above those encountered in radio broadcasting and similar high-voltage power applications.

The requirements in the process for separating the uranium atoms limit the maximum permissible variation in the value of high voltage supplied to the apparatus to approximately 0.04 per cent of the mean voltage. Such precise regulation of high amounts of power at high voltages, to a load that intermittently acts as a short circuit, had never before been attained.

Because of the great scarcity of copper, and because time was more precious than gold, 27,680,000 pounds of silver, worth $400,000,000, were borrowed from the Treasury Department for use as winding coils and busbars for the multitudinous magnets. The solid silver winding coils have a total length of more than 900 miles.

Silver is as good a conductor of electricity as copper and is not harmed by the passage of current. The silver will be returned to the Treasury when conditions warrant. Meantime this great plant for producing the material for the atomic bomb is, among other things, also a "branch office of the Treasury."

All the research involving the electromagnetic method for concentrating U-235 was carried out under Government contract at the University of California under the direction of Professor Lawrence. At the peak of the research, August, 1943, Dr. Lawrence was assisted by a staff of 1,266, including 465 laboratory and research workers, and 365 employed in plant operation.

Following is the sixth of a number of of articles by a staff member of The New York Times who was detached for service with the War Department at its request to explain the atomic bomb to the lay public. He witnessed the first test of the bomb in New Mexico and, on a flight to Nagasaki, its actual use.

In "Atomland-on-Mars," where the impossibles of yesterday have become actualities taxing credulity, the privileged visitor is shown a strange building, resembling a fair-sized football stadium and covering an area of several million square feet.

It is one of the gigantic plants where the foundations are being laid for the civilization of tomorrow. It is here where uranium 235 (U-235), the element yielding great amounts of atomic energy, is being concentrated by a method entirely different from the electromagnetic method, previously described in these articles.

At the time when the Atomic Bomb Project, known as the Manhattan Engineer District, was organized under the auspices of the Army Corps of Engineers, a number of possible methods for concentrating U-235 were under consideration by our scientists. Each method presented tremendous obstacles. Since we were entering the darkest jungles of the "Dark Africa of Matter," where many an unknown danger awaited us, it was decided to explore the new continent of the atom by several different routes, so that if one failed the other might succeed.

Accordingly, several different types of plants, each employing a different method for producing U-235, as well as other plants for producing Element 94, or plutonium, the man-made element not found in nature, were constructed at secret sites in widely separated sections of the country. In every one of them tremendous obstacles, many of them unforeseen, were successfully overcome.

Yesterday these mammoth plants produced the raw materials for the atomic bomb. Tomorrow these same materials may be used for ushering in the new Age of Atomics, or Nucleonics, an age in which man will have at his disposal the practically inexhaustible energy that nature has locked up in the nuclei of the atoms of which the material universe is constituted.

Like the electromagnetic plant' for separating U-235, the stadium-shaped plant is also part of the mammoth Clinton Engineer Works, situated on the 59,000-acre Government reservation in the Tennessee Valley, eighteen miles northwest of Knoxville. In this plant, however, the method of concentration of the U-235 is based on the principle governing the diffusion of gases known as Graham's Law, as elaborated on by Lord Rayleigh as far back as 1896.

According to Graham's Law, the rates of diffusion of different gases' through a porous material are, under similar conditions, inversely proportional to the square roots of the molecular weights of the gases. For example, if one gas, A, has a molecular weight of 9, and another gas, B, has a molecular weight of 16, the rate of diffusion of gas A through a porous medium, as compared with the rate of diffusion of gas B, will be in the ratio of 4 volumes of gas A (the lighter gas) to 3 volumes of gas B.

When a mixture of gas A and gas B is allowed to diffuse through a suitable porous medium, under ideal conditions, the ratio of gas A to gas B, in the portion first passing through the medium, will thus be 1.33 times greater than the original ratio of A to B. By subjecting the portion first diffused to the same process a gas mixture in which the ratio of A to B is increased by a second factor of 1.33 can be obtained. In fact, the process can be repeated at will, finally achieving any desired ratio of A to B.

In a practical plant, however, the separation factor in this particular example will not reach the ideal value of 1.33, but may go as high as 1.2.

As an example of such a plant, Iet us assume that the ratio of gas A to gas B is 1 to 50 and we want to change it to 1,000 to 1. Assuming that we obtain an increase in ratio of 1.2 of A to B at each stage, we would require al plant in which the diffusion process is repeated sixty times.

When our scientists and engineers first considered the possibility of separating U-235 from the U-238 by the gaseous diffusion method in accordance with the Graham-Rayleigh principle they were confronted with a host of obstacles that at first seemed insurmountable.

Applying our example to the case of uranium will illustrate the magnitude of the separation problem. Since uranium itself is not a gas, some gaseous compound of uranium had to be used. The only uranium compound at that time known that could be converted into a suitable stable gas was uranium hexafluoride, a combination of one atom of uranium and six atoms of fluorine, that would corrode practically anything with which it comes in contact.

Not only is this gas highly reactive but it is actually a solid at room temperature and atmospheric pressure.

For these reasons a study of other gaseous compounds of uranium was urgently undertaken. As insurance against failure in this search for alternative gases, it was necessary to continue work on uranium hexafluoride, as in devising methods for producing and circulating the gas.

It was realized from the beginning that a plant for concentration of U-235 by the gaseous diffusion method had to be of enormous dimensions, regardless of whether uranium hexafluoride or some other type of uranium gas was used.

This can be illustrated by taking uranium hexafluoride as an example, though it would apply to other uranium gases as well. The molecular weight of the uranium 238 hexafluoride is 352, whereas the uranium-fluorine gas containing six atoms of fluorine and one atom of uranium 235 has a molecular weight of 349.

Since, according to the Graham Law, the rate of diffusion of the gas containing U-235, as compared with the gas containing uranium 238, would be inversely proportional to the square roots of their molecular weights—that is, in the ratio of the square root of 352 (18.76) to the square root of 349 (18.68)—the increase of the concentration of the U-235 hexafluoride would be by a factor of only 1.0043. Under actual operating conditions this value is even smaller.

This is, indeed, a verge small enrichment factor. Hence, to bring it up to the desired level, it became necessary to design and construct a gigantic cascade in which the gas to be separated is made to pass through thousands of successive stages, each stage enriching the proportion of the U-235 gas over the preceding stage, the enriched mixture passing on to the next stage where it is further enriched. No such plant for separation of gases had ever been designed or even conceived.

One of the principal problems that had to be solved before the plant could be built involved the development of a suitable porous medium, or barrier, through which the uranium gas mixture had to be diffused in a manner to allow a greater proportion of U-235 to pass through, as compared with U-238.

It has been established that the pores of the barrier through which a gas mixture is diffused must be considerably smaller than the average distance a gas molecule travels before it collides with another gas molecule, a distance known as the "mean free path." At atmospheric pressure the mean free path of a molecule is of the order of a ten-thousandth of a millimeter or a tenth of a micron. To insure true diffusive flow of the gas the diameter of the myriad holes in the barrier must be less than one-tenth of the mean free path—that is, about one-hundredth of a micron, or about four ten-millionths of an inch.

Such a barrier must have billions of holes of this size or smaller. Furthermore, these holes must not enlarge or plug up as the result of direct corrosion or dust coming from corrosion elsewhere in the system. The barrier must be able to withstand the pressure "head" of one atmosphere. It also had to be of a type that could be manufactured in large quantities and with uniform quality.

It was further realized that thousands of powerful pumps would be needed and thousands of kilowatts to operate them. Too, that the whole circulating system would have to be made vacuum tight and leak proof, requirements presenting problems of a magnitude never faced before. This vast plant is now operating successfully after surmounting every obstacle.

A new industry had to be developed to manufacture the porous barrier, for the gaseous diffusion.

This is, indeed, a verge small enrichment factor. Hence, to bring it up to the desired level, it became necessary to design and construct a gigantic cascade in which the gas to be separated is made to pass through thousands of successive stages, each stage enriching the proportion of the U-235 gas over the preceding stage, the enriched mixture passing on to the next stage where it is further enriched. No such plant for separation of gases had ever been designed or even conceived.

One of the principal problems that had to be solved before the plant could be built involved the development of a suitable porous medium, or barrier, through which the uranium gas mixture had to be diffused in a manner to allow a greater proportion of 15-235 to pass through, as compared with U-238.

It has been established that the pores of the barrier through which a gas mixture is diffused must be considerably smaller than the average distance a gas molecule travels before it collides with another gas molecule, a distance known as the "mean free path." At atmospheric pressure the mean free path of a molecule is of the order of a ten-thousandth of a millimeter or a tenth of a micron. To insure true diffusive flow of the gas the diameter of the myriad holes in the barrier must be less than one-tenth of the mean free path—that is, about one-hundredth of a micron, or about four ten-millionths of an inch.

Such a barrier must have billions of holes of this size or smaller. Furthermore, these holes must not enlarge or plug up as the result of direct corrosion or dust coming from corrosion elsewhere in the system. The barrier must be able to withstand the pressure "head" of one atmosphere. It also had to be of a type that could be manufactured in large quantities and with uniform quality.

It was further realized that thousands of powerful pumps would be needed and thousands of kilowatts to operate them. Too, that the whole circulating system would have to be made vacuum tight and leak proof, requirements presenting problems of a magnitude never faced before. This vast plant is now operating successfully after surmounting every obstacle.

A new industry had to be developed to manufacture the porous barrier, for the gaseous diffusion.

To satisfy the demands for power, a huge powerhouse was constructed, the largest initial single installation of its kind ever built. The scientific research work on the diffusion process was initiated by Prof. John R. Dunning of Columbia University, and was carried on in a large building in upper Manhattan, under a contract between Columbia and the Office of Scientific Research and Development (OSRD), until May 1, 1943, when the work was taken over by the Manhattan Engineer District.

In 1942 the M. W. Kellogg Company was chosen to plan the large-scale plant. For these purposes that company created a special subsidiary, the Kellex Corporation, and placed Dr. P. C. Keith in charge of it. The Kellex Corporation not only planned and procured materials for the large-scale plant, but also carried on research and development in its Jersey City laboratories and with the Columbia group. The plant was constructed by the J. A. Jones Construction Company, Inc., of Charlotte, N. C.

In January, 1943, Carbide and Carbon Chemicals Corporation was selected as the operator of the plant. Its engineers soon began to play a large role not only in the planning and construction but also in the research work.

Construction of the main process plant began Sept. 10, 1943, and the plant was in successful operation before the summer of 1945.

Following is the seventh of a number of articles by a staff member of The New York Times who was detached for service with the War Department at its request to explain the atomic bomb to the lay public. He witnessed the first test of the bomb in New Mexico and, on a flight to Nagasaki, its actual use.

When the full details of the development of the atomic bomb can finally be told the story of the creation, production and purification of Element 94, named plutonium, will stand out as one of the great epics of history and as a distinct turning-point in the life of man on earth.

ln this achievement our scientists not only have realized the dream of the ages, the transmutation of one element into another; they have accomplished what even the ancient alchemists did not dare dream about. For not only have they succeeded in transmuting one element into another, in relatively enormous quantities, they have created an entirely new element that never before was known to exist in nature, an element that, like U-235, releases enormous amounts of atomic energy.

It is as if nature had become tired after creating uranium, her ninety-second element, and decided to "call it day." Now comes man and takes up the work where nature left off billions of years ago.

To understand how this was done requires the statement of some elementary facts about the constitution of the nuclei of atoms, in which more than 99.999 per cent of the mass and energy of the material universe is concentrated.

The nuclei are composed of two types of fundamental particles, protons and neutrons. Both have about the same mass, or atomic mass 1. But whereas the proton a constant fundamental unit of positive electricity, the neutron, as its name implies, is electrically neutral.

The discovery of the neutron in 1932 by Sir James Chadwick, then at the Cavendish Laboratory, Cambridge University, England, for which he won the Nobel Prize and knighthood, ranks with the greatest scientific discoveries of all time. It was this discovery that finally gave man the key to the atom. It opened the way for the transmutation of the elements and for the release of atomic energy. It made possible the atomic bomb and holds the promise for greater things to come. It is the Philosopher's Stone the alchemists looked for in vain.

While much still remains to be learned about the neutron, enough about it has been learned during the past ten years to make it the most useful tool in the study of the atom. It behaves differently under different conditions. Under certain conditions it acts in the manner of a particle that carries both a positive and a negative fundamental unit of electrical charge of equal magnitude. The two electrical charges thus balance one another, making the particle electrically neutral.

By the use of the cyclotron, gigantic atomic "merry-go-round" apparatus, neutrons can be fired at tremendous energies at the nuclei of atoms. Some of these neutrons penetrate the nucleus and remain there. When that happens the atomic weight of "the atom is increased by one atomic mass unit. In that event the particular element does not change in identity. It becomes what is known as an "isotope" of the element, slightly heavier in weight, but still possessing the same chemical characteristics.

In many cases, however, the entry of a new neutron produces a cosmic cataclysm inside the nucleus, setting to work mighty forces greater, in proportion, than the eruption of the greatest terrestrial volcano or the most devastating earthquake.

When this atomic eruption takes place it often manifests itself in the emission of a negative charge of electricity, generally referred to as a beta particle, or negative electron. This negative electron comes from one of the neutrons in the nucleus.

Since that particular neutron originally had both a negative and a positive charge of electricity, the loss of the negative charge changes its character entirely. It is no longer an electrically neutral particle, for it now has a positive charge of electricity. In other words, the neutron has become a proton.

The atom to which this happens thus gets not only an extra unit of atomic weight but also an extra unit of positive electricity in its nucleus. This brings about a fundamental change in the nature of the atom, creating an entirely different element, since the nature and properties of the various elements depend entirely on the number of positively charged particles—i.e. protons, in their nucleus.

The material universe as we know it is made up of ninety-two elements, beginning with hydrogen, the lightest of the elements at one end of the atomic table and ending with uranium, the heaviest of the natural elements at the other end. The elements are numbered from 1 to 92, each number corresponding to the number of positive electrical particles in the nuclei of their atoms. Thus hydrogen, with atomic No. 1, has one positive particle, or proton, in its nucleus; helium, atomic No. 2, aas two protons; lithium, the third element, has 3; and so on, up to uranium, the ninety-second and last natural element, which has ninety-two protons in the nucleus of its atom.

In addition to the protons, the nuclei of the atoms of most of the elements also contain neutrons. The effect of this is to make their atomic weight greater than the atomic number, this increase in weight depending on the number of neutrons, each neutron, as well as each proton, having an atomic mass value of 1.

For example, carbon occupies atomic No. 6 on the Periodic Table of Elements. This means it contains 6 protons in its nucleus. But it has an atomic weight of 12. This means that in addition to the 6 protons its nucleus also has 6 neutrons.

Similarly with uranium. It occupies atomic No. 92 on the Periodic Table. This means its nucleus contains 92 protons. One form (isotope) of uranium has an atomic weight of 238. Subtracting 92 from 238 gives the number of neutrons in the uranium nucleus as 146.

Another form of uranium known as uranium 235, the spectacular atomic energy element, still occupies No. 92 on the Periodic Table. But its atomic weight is 235. This means that it has the same number of protons in its nucleus as uranium 238 (U-238) but 3 fewer neutrons.

With these facts in mind we are now ready to understand the basic principles of the creation of plutonium, Element 94. We start with uranium 238. A neutron is fired into its nucleus. This sets in motion a series of cosmic events of tremendous consequences.

The neutron first lodges In the nucleus of the uranium 238 atom. This increases the atomic weight of the atom by 1 mass unit. The element is still uranium, but instead of an atomic weight of 238 it now has a mass of 239. It has 147 neutrons instead of 146.

But this form of uranium 239 has a rather turbulent and hectic existence. Atomic eruptions take place of super-volcanic dimensions. Soon a negative electric charge—namely, a beta particle—comes flying out.

This negative particle is lost by one of the 147 neutrons in the uranium 239 nucleus. As explained earlier, that neutron is now left with a positive charge. It is now a proton. In other words, the uranium 239 now has only 146 neutrons in its nucleus. But instead of its original 92 protons it now has 93.

This means that a new element has been created out of the uranium, Element 93 out of Element 92. Since uranium was named after the planet Uranus, the element beyond uranium was named neptunium, after Neptune, the planet beyond Uranus.

But the volcanic eruptions started by the original neutron does not end here. Neptunium, an element that was not known to exist in nature, also has a turbulent short life.

In a short time a negative electron (beta particle) comes shooting out of its nucleus. The same process repeats itself. One of the 146 neutrons in the neptunium nucleus, having lost its negative electrons, becomes transmuted into a proton.

This means that the nucleus of the element now has ninety-four protons and only 145 neutrons. It still has the same atomic weight of 239 but it is now once again an- entirely new element, totally different from both uranium 238, its grandparent, and its immediate ancestor, neptunium.

How this transmutation was achieved on a mass-production basis will be told in a subsequent article.

Following is the ninth of a number of articles by a staff member of The New York Times who was detached for service with the War Department at its request to explain the atomic bomb to the lay public. He witnessed the first test of the bomb in New Mexico and, on a flight to Nagasaki, its actual use.

A host of formidable new problems such as science had never faced before had to be overcome not only in the production of plutonium, but also in its chemical separation from its uranium parent and in its purification and preparation for use in the atomic bomb. 

It was necessary to develop an entirely new chemistry for concentrating this new element; new processes and new plants had to be designed and built. Moreover, to protect those handling this newly born livest of "live coals" against the most dangerous radiations ever produced on earth, plants had to he designed to perform by remote control all the complicated operations involved.

When plutonium was first discovered at the University of California Radiation Laboratory in March, 1941, and the building of atomic piles for producing it in large quantities was first contemplated, some leaders in chemistry feared that it might take at least five years to develop the chemical methods involved. This, of course, would have been too late for use in the war. 

However, when this question was put before the young group of physicists and chemists who had produced the first minute bits of plutonium, including Dr. Glenn T. Seaborg, Dr. Joseph W. Kennedy and Dr. Arthur C. Wahl, they expressed the belief that they could develop methods for chemical purification in a much shorter time. 

Since no more than microgram (one-millionth of a gram) amounts of plutonium could be made by the methods then available, it became necessary to work on an extremely small scale of operation, namely, the so-called "ultra-micro scale." 

The first plutonium in the form of a compound was isolated on Aug. 18, 1942, by Drs. B. B. Cunningham and L. B. Werner, and a number of compounds were made as early as September, 1942. Work continued on this microgram scale of operations for about a year and a half. 

On the basis of these "bits of nothing" our chemists proceeded to design a huge chemical plant to scale, the "microgram plant" serving as a "pilot plant" for actual operations some ten billion times greater in scope. 

To do so they had to use a host of chemicals in exact proportions, which meant that they had to be used in quantities of micrograms and fractions of micrograms, within a limit of accuracy of 3 percent. A human breath weighs about 750,000 micrograms, while a dime weighs 2,500,000 micrograms. 

To achieve this unheard-of accuracy in weighing, an ultra-micro balance of an extremely high sensitivity was designed and built by Drs. P. L. Kirk and R. D. Craig of the University of California. This balance could actually weigh amounts as small as a microgram with an accuracy of 3 per cent, and could actually weigh a mass as small as 0.03 micrograms. The material to be weighed before it could be placed in containers weighing as much as twenty milligrams—that is, 20,000 micrograms. 

The beam and other operating parts of this balance are constructed of fibers of pure quartz ranging in diameter from about four times that of a human hair down to fibers that are invisible to the unaided eye. The beam of the balance is a quartz fiber framework some four inches in length, which is suspended inside a brass housing on a horizontal fiber at right angles to the plane of the beam. 

From each end of the beam there depends a fiber, to which is attached a quartz frame that holds a weighing pan of thin platinum foil. Objects to be weighed are placed on the foil. 

The addition of a weight to one side of the balance causes the beam to be depressed on that side. The beam is restored to its initial position by twisting in the opposite direction on the fiber that supports it. It is the amount of twisting necessary to return the beam to its initial position, after the addition of a weight, that is measured and used to evaluate the weight added. 

The movement of the beam is magnified by a suitable optical arrangement, and during a weighing all parts of the balance are protected against air currents. 

Work continued on approximately this scale of operation until about January, 1944, at which time milligram amounts of plutonium became available. There soon followed experiments on the gram and then on the ten-gram scale. Following these the scale became substantially larger. 

On the basis of these ultra-micro scale procedures a large pilot plant was built at the Clinton Engineer Works in Tennessee, where the chemistry for concentrating and purifying plutonium was further developed under the direction of Prof. Warren Johnson of the University of Chicago, and Maj. Oswald H. Greager, formerly of the du Pont Company. 

Before this pilot plant was completed, however, work began on three huge separation plants on the 430,000-acre Government Reservation near Pasco, in the State of Washington. These plants, rectangular structures hundreds of feet long, are the most remarkable chemical factories ever conceived or designed. In them enormous quantities of materials are made to go through complicated chemical processes with no human eye ever seeing what actually goes on except through a complicated series of dials and panels that enable the operators to maintain perfect control of every single operation at all times. 

Each operation is performed in a remote cell behind thick walls, and when it is completed the treated material invisibly moves on to the next cell, until at the end of a series of such passages the miracle of modern alchemy emerges, ready for the next stage on its ultimate journey.