FOREWORD

LiFE - LINE, MISFIT, LET THERE BE LIGHT, ELSE WHEN, PIED PIPER, IF THiS GOES ON - , REQUIEM, THE ROADS MUST ROLL, COVENTRY, BLOWUPS HAPPEN - for eleven months, mid March 1939 through mid February 1940, I wrote every day.. and that ended my bondage; BLOWUPS HAPPEN paid off the last of that pesky mortgage - eight years ahead of time.

BLOWUPS HAPPEN was the first of my stories to be published in hard covers, in Groff Conklin's first anthology, THE BEST OF SCIENCE FICTION, 1946. In the meantime there had been World War II, Hiroshima, The Smyth Report - so I went over my 1940 manuscript most carefully, correcting some figures I had merely guessed at in early 1940.

This week I have compared the two versions, 1940 and 1946, word by word - there isn't a dime's worth of difference between them... and I now see, as a result of the enormous increase in the art in 33 years, more errors in the '46 version than I spotted in the '40 version when I checked it in '46.

I do not intend ever again to try to update a story to make it fit new art. Such updating can't save a poor story and isn't necessary for a good story. All of H. G. Wells' SF stories are hopelessly dated... and they remain the best, the most gripping science fiction stories to be found anywhere. My BEYOND THIS HORIZON (1941) states that H. sapiens has forty - eight chromosomes, a "fact" that "everybody knew" in 1941. Now "everybody knows" that the "correct" number is forty - six. I shan't change it.

The version of BLOWUPS HAPPEN here following is exactly, word for word, the way it was first written in February 1940.

Blowups Happen

"PUT down that wrench!"

The man addressed turned slowly around and faced the speaker. His expression was hidden by a grotesque helmet, part of a heavy, lead - and - cadmium armor which shielded his entire body, but the tone of voice in which he answered showed nervous exasperation.

"What the hell's eating on you, doc?" He made no move to replace the tool in question.

They faced each other like two helmeted, arrayed fencers, watching for an opening. The first speaker's voice came from behind his mask a shade higher in key and more peremptory in tone. "You heard me, Harper. Put down that wrench at once, and come away from that 'trigger'. Erickson!"

A third armored figure came from the far end of the control room. "What 'cha want, doe?"

"Harper is relieved from watch. You take over as engineer - of - the - watch. Send for the standby engineer."

"Very well." His voice and manner were phlegmatic, as he accepted the situation without comment. The atomic engineer whom he had just relieved glanced from one to the other, then carefully replaced the wrench in its rack.

"Just as you say, Doctor Silard, but send for your relief, too. I shall demand an immediate hearing!" Harper swept indignantly out, his lead - sheathed boots clumping on the floorplates.

Doctor Silard waited unhappily for the ensuing twenty minutes until his own relief arrived. Perhaps he had been hasty. Maybe he was wrong in thinking that Harper had at last broken under the strain of tending the most dangerous machine in the world - the atomic breeder plant. But if he had made a mistake, it had to be on the safe side - slips must not happen in this business; not when a slip might result in atomic detonation of nearly ten tons of uranium - 238, U - 235, and plutonium.

He tried to visualize what that would mean, and failed. He had 'been told that uranium was potentially twenty million times as explosive as T.N.T. The figure was meaningless that way. He thought of the pile instead as a hundred million tons of high explosive, or as a thousand Hiroshimas. It still did not mean anything. He had once seen an A - bomb dropped, when he had been serving as a temperament analyst for the Air Forces. He could not imagine the explosion of a thousand such bombs; his. brain balked. Perhaps these atomic engineers could. Perhaps, with their greater mathematical ability and closer comprehension of what actually went on inside the nuclear fission chamber, they had some vivid glimpse of the mind - shattering horror locked up beyond that shield. If so, no wonder they tended to blow up - He sighed. Erickson looked away from the controls of the linear resonant accelerator on which he had been making some adjustment.

"What's the trouble, doc?"

"Nothing. I'm sorry I had to relieve Harper."

Silard could feel the shrewd glance of the big Scandinavian. "Not getting the jitters yourself, are you, doc? Sometimes you squirrel - sleuths blow up, too - "

"Me? I don't think so. I'm scared of that thing in there - I'd be crazy if I weren't."

"So am I," Erickson told him soberly, and went back to his work at the controls of the accelerator. The accelerator proper lay beyond another shielding barrier; its snout disappeared in the final shield between it and the pile and fed a steady stream of terrifically speeded up sub - atomic bullets to the beryllium target located within the pile itself. The tortured beryllium yielded up neutrons, which shot out in all directions through the uranium mass. Some of these neutrons struck uranium atoms squarely on their nuclei and split them in two. The fragments were new elements, barium, xenon, rubidium - depending on the portions in which each atom split. The new elements were usually unstable isotopes and broke down into a, dozen more elements by radioactive disintegration in a progressive reaction.

But these second transmutations were comparatively safe; it was the original splitting of the uranium nucleus, with the release of the awe - inspiring energy that bound it together - an incredible two hundred million electron volts - that was important - and perilous.

For, while uranium was used to breed other fuels by bombarding it with neutrons, the splitting itself gives up more neutrons which in turn may land in other uranium nuclei and split them. If conditions are favorable to a progressively increasing reaction of this sort, it may get out of hand, build up in an unmeasurable fraction of a micro - second into a complete atomic explosion - an explosion which would dwarf an atom bomb to pop - gun size; an explosion so far beyond all human experience as to be as completely incomprehensible as the idea of personal death. It could be feared, but not understood.

But a self - perpetuating sequence of nuclear splitting, just wider the level of complete explosion, was necessary to the operation of the breeder plant. To split the first uranium nucleus by bombarding it with neutrons from the beryllium target took more power than the death of the atom gave up. In order that the breeder pile continue to operate it was imperative that each atom split by a neutron from the beryllium target should cause the splitting of many more.

It was equally imperative that this chain of reactions should always tend to dampen, to die out. It must not build up, or the uranium mass would explode within a time interval too short to be measured by any means whatsoever.

Nor would there be anyone left to measure it.

The atomic engineer on duty at the pile could control this reaction by means of the "trigger", a term the engineers used to include the linear resonant accelerator, the beryllium target, the cadmium damping rods, and adjacent controls, instrument board, and power sources. That is to say he could vary the bombardment on the beryllium target to increase or decrease the level of operation of the plant, he could change the "effective mass" of the pile with the cadmium dampers, and he could tell from his instruments that the internal reaction was dampened - or, rather, that it had been dampened the split second before. He could not possibly know what was actually happening now within the pile - subatomic speeds are too great and the time intervals too small. He was like the bird that flew backward; he could see where he had been, but never knew where he was going.