their readiness to react. When the dissolving is complete, the temperature is raised to 218 degrees centigrade and kept there for thirteen hours. During this time the desired reaction takes place; in brief, the molecules of these two compounds all unite to form an exceedingly long chain of carbon atoms, bound one to another by atoms of nitrogen and oxygen. From this results a new compound with properties utterly different from those of the raw materials used to make it: the new compound is sticky and elastic at the high temperature at which the reaction is carried out, while the two original substances from which it is made are two white powders which no observer would suppose to have the remotest connection with nylon.

And now that the chemical reaction is finished and the various molecules have united, the contents of the steel boiler are poured into a vessel consisting of a large quantity of alcohol (that is, ordinary spirits); and since nylon does not dissolve in alcohol, it settles to the bottom of the vessel as an ivory-white substance. The alcohol is then removed from it and it is thoroughly dried.

This is raw nylon, and from it are spun the threads used in making stockings and "nylon" fabrics. To this end the raw nylon is taken and subjected to high heat until it melts and turns into a liquid;

this liquid is then forced through minute holes, from which it issues as long threads that are wound on spools prepared especially for the purpose. But these threads cannot yet be used for weaving fabrics, for they are still more elastic than they should be; add to this that they break easily. This comes of the fact that the molecules composing the thread are not drawn up in serried ranks but are arranged haphazard. Just as a man who tries, for example, to gather up his papers or his belongings in haste ends with an untidy bundle, so the molecules in the threads of raw nylon are still scattered and unordered, and they must all be ranged in serried ranks before we have a strong thread. To reach this end, the nylon thread is transferred from its old spools to new spools revolving at four times the speed of the old ones. The threads therefore do not merely pass from one spool to another: in the course of passing they are stretched, so that the thread's length increases fourfold, and it gains in luster and strength, because its molecules have all become ordered and regular. Here it has reached the stage at which it can be used industrially in the knitting of stockings or of the various textiles.

Nylon is still an infant in the world of industry — America began producing it industrially at the beginning of 1940 — so the time has not yet come to foretell the future of this new material. But there is no doubt that in the inven-tion of nylon lies fresh evidence of man's productive genius, and one proof more of what science is doing in the service of man.