With these facts and figures in mind, it becomes clear that an H-bomb made of deuterium alone is not feasible. It is certainly out of the question with an A-bomb of the Hiroshima or Nagasaki types, which generate a temperature of about 50,000,000 degrees, since, as we have seen, it would take fully 200 microseconds to ignite it at that temperature. It is one thing to devise a tamper that would hold back a force of 20 tons for 100 billionths of a second, and thus allow it to build up to 20,000 tons. It is quite another matter to devise an immovable body that would hold back an irresistible force of 20,000 tons for a time interval 2,000 times larger, particularly if one remembers that in another tenth of a microsecond the irresistible force would increase again by 1,000 to 20,000,000 tons. Obviously this is impossible, for if it were possible we would have a superbomb without any need for hydrogen of any kind. It is known that we have developed a much more efficient A-bomb, which, as Senator Edwin C. Johnson of Colorado has inadvertently blurted out, “has six times the effectiveness of the bomb that was dropped over Nagasaki.” We are further informed by Dr. Bacher that “significant improvements” in atomic bombs since the war “have resulted in more powerful bombs and in a more efficient use of the valuable fissionable material.” It is conceivable and even probable that the improvements, among other things, include better tampers that delay the new A-bombs long enough to fission two, four, or even eight times as many atoms as in the wartime models. But since, as we have seen, the ten steps of the final stages require only an average of 10 billionths of a second per step, increasing the power of the new models even to 160,000 tons (eight times the power of the Hiroshima type) would take only three steps, in an elapsed time of no more than 30 billionths of a second. And even if we assume that the improved bomb generates a temperature of 200,000,000 degrees, it would still be too cold to ignite the deuterium during the interval of its brief existence, since, as we have seen, it would take 4.8 microseconds to ignite it at that temperature. In fact, calculations indicate that it would require a temperature in the neighborhood of 400,000,000 degrees to ignite deuterium in the time interval during which the assembly of the improved A-bomb appears to be held together, which, as may be surmised from the known data, is within the range of 1.2 microseconds. From all this it may be concluded with practical certainty that an H-bomb of deuterium only is out of the question. Equally good, though entirely different, reasons also rule out an H-bomb using only tritium as its explosive element.