Page:Popular Science Monthly Volume 80.djvu/444

440 time and of careful work. We are at present engaged not only in checking this value under new sets of conditions, but in redetermining all of the quantities which enter into it. Assuming it as the basis of our computation there are in a cubic centimeter of gas under normal conditions $$2.70 \times 10^{19}$$ molecules and the weight of a hydrogen atom is $$1.735 \times 10^{-24}-grams$$. These numbers can be made more significant to the ordinary reader with the aid of an illustration. If a million men were to be set counting as fast as they could count, say at the rate of 200 a minute, they could count out the number of molecules in a cubic centimeter in just 252 thousand years if none of them ever stopped to eat, sleep, or die.

"But," says some one, "What of it any way? Does the triumph or defeat of the kinetic theory of matter or the atomic theory of electricity have anything to do with the practical problems of the modern world? Is anybody going to be better fed or better clothed because of it?" the answer is, "Within the past seventy-five years—the merest drop in the bucket of recorded time—the conditions of human life on this earth have been completely revolutionized, and that solely because, for the first time in history, man has become interested in considerable numbers, rather than, as heretofore in isolated instances, in patiently and persistently seeking merely to uncover nature's 'useless' secrets, and then, when the inner workings have been laid bare, has in many cases seen a way to put his brain inside the machine and drive it where he would. Every increase then in man's knowledge of the way in which nature works must in the long run increase by just so much man's ability to control nature and to turn her hidden forces to his own account."