We thus have a threefold answer to the question: Can the H-bomb _actually_ be made? As we have seen, the deuterium bomb is definitely not possible. The tritium bomb is theoretically possible, but definitely not practicable. But a large deuterium bomb using a reasonably small amount of a deuterium and tritium mixture as extra kindling is both possible and feasible. We now also stand on solid ground in dealing with the questions of cost and of the time it would take us to get into production. With these questions answered, we can then decide whether the H-bomb, if made, will add enough to our security to make the effort worth while. We know at this stage that the H-bomb requires three essential ingredients. It needs, first of all, an A-bomb to set if off. We have a sizable stockpile of them. It needs large quantities of deuterium. We have built several deuterium plants during the war, and they should be large enough to supply our needs. Since it is extracted from water, the raw material will cost us nothing. The only item of cost will be the electric power required for the concentration process, and this should not be above $100 per kilogram, and probably less. The third vital ingredient, tritium, can be made in the giant plutonium plants at Hanford, Washington. Thus it can be seen that all the essential ingredients of the H-bomb, the costliest and those that would take longest to produce, as well as the multimillion-dollar plants required for their production, are already at hand. This means that as far as the essential materials are concerned, we are ready to go right now. And as for the cost, it would appear to require hardly any new appropriations by Congress, or, at any rate, only appropriations that would be mere chicken feed compared with the five billion we have already invested in our A-bomb program. The raw material out of which tritium is made is the common, cheap light metal lithium, the lightest, in fact, of all the metals. It has an atomic weight of six, its nucleus consisting of three protons and three neutrons. When an extra neutron invades its nucleus, it becomes unstable and breaks up into two lighter elements, helium (two protons and two neutrons) and tritium (one proton and two neutrons). They are both gases and they are readily separated. And while lithium of atomic weight six constitutes only 7.5 per cent of the element as found in nature (it comes mixed with 92.5 per cent of lithium of atomic weight seven), there is no need to separate it from its heavier twin, since the latter has no affinity for neutrons and nearly all of them are gobbled up by the lighter element.