Page:Popular Science Monthly Volume 21.djvu/81

Rh facts, that woman's smaller heart beats faster than man's larger one; that her circulation is to his in swiftness as ten to nine; and that, according to Miss Hardaker's figures, and to some celebrated authorities, the proportion of brain to body is larger in woman than in man.

But to meet Miss Hardaker upon her own ground in the discussion of her fundamental propositions, we shall waive, as she has done, all sexual differences, of physical or local environment, and all analogical inferences, and proceed to compare the male and female brains upon a supposititious level of like conditions. She proposes to prove, on quite new and highly scientific grounds, that absolute weights and measurements are, after all, the ultimate tests of capacity. It may be deemed singular that the profound students who have preceded Miss Hardaker—some of whom were undoubtedly scientists—should have entirely overlooked the beautifully simple conclusion she formulates, thus: "If mass represents force, the larger the brain, the larger the power." The reason why students have been so blind to Miss Hardaker's discoveries is quite as simple as the discovery itself. It is because her premises are false.

A large amount of matter does not represent more force than a small amount, nor does it represent any force at all. There is an elementary law of physics which declares that the momentum of a body equals its size multiplied by its velocity, and this may lead to the supposition that matter itself is force. But matter in a state of inertia is not power; it becomes powerful only when acted upon. The same force acting upon different bodies imparts velocity in the inverse ratio of their masses; and, since velocity as well as size is a factor of power, it follows that a force which imparts a greater velocity to a smaller body gives it as great a momentum as a larger body obtains when acted upon by the same force; for the velocity in the latter case is feebler. Even admitting (what Miss Hardaker does not appear to claim) that potential energy may be proportionate to size of mass, we see that potential energy can only be evolved by an appropriate force acting through or upon the mass, and, to make the potential energy of a large mass do more work than that of a smaller one, the force applied must always be greater. Hence, not the size of the body, but the strength of the impelling force, is the ultimate test of its power. A glance at obvious facts will show that size is not the gauge, that weight may indeed be a direct impediment to the evolution of force. The avoirdupois of the fat boy is a clog to his energy; the fast runner wins by his light weight; the champion oarsman reduces his flesh.

In applying her theory to the brain, one fact which Miss Hardaker herself states is sufficient to tell very disastrously against her conclusion that larger brain-weight means larger thinking power. "According to Gratiolet, the male brain can not fall below thirty-seven ounces without involving idiocy, while the female may fall to thirty-two