Page:Popular Science Monthly Volume 22.djvu/820

800 frequency to a second of time that a second (or a wave of the hand) bears to 30,000,000 years—one of the geologic periods, during which a race of animals may have been evolved and have perished.

Such inconceivable velocity of rhythmical motion in the elementary molecule points to some cause more potent than the action of any mere static force combined with any mere energy of position. The same is true of the more complex molecules of our experience—say of iron, or calcium—displaying hundreds of spectral lines. We can not suppose these inconceivably energetic motions to have been all set up by any mere precipitation which evolved the element, nor to have existed in their present organization from eternity. The same is, of course, true of the organic molecule. Their conserved energy lies in the vast reserve of vis viva stored up in their complex interior movements. A few ounces of organized food suffice for the expenditure of a mountain-climber for a whole day. An apparently inert explosive is traversed by a tiny spark, or pressed too closely, and the increased swing of one molecular orbit sets off the whole mass into new paths and more economical relations by which a vast amount of motion is liberated, to appear as temperature. This temporarily expands the w r hole mass many volumes, but, as the agitation subsides, the now surplus energy dissipates by radiation, and, being picked up by surrounding bodies, temperature becomes equalized. This mechanical modification and distribution of motions, resulting in final equilibrium, is more intelligible than the instantaneous setting up of immense velocities and momenta by precipitation from a state of absolute rest.

Besides, research proves that there is absolutely no room for any such energy of position as was fancied. Sir William Thomson has shown, by considerations of high probability ("Nature," vol. i, page 553), that the distance from center to center of molecules in solids and liquids can be but little more than the diameter of the molecules. In liquids, from their great resistance to compression, the practical point of contact has been reached, but temperature conserves mobility.

The phrase "dead matter," once deemed so eminently characteristic, now seems absurd. To deprive matter of its inherent activity is indeed one of the most difficult problems we can encounter. To do it, some means for the disposal and transfer of its energy must be provided. Until very recently, no means were contrivable for subduing the elementary gases, but, by resorting to the most extraordinary compression, in conjunction with the lowest temperature procurable by artificial means, the feat has been accomplished. There is a way, however, of pitting certain elements against each other by taking advantage of their commensurate atomic periods, and in this way we get our chief supply of artificial heat. This is due to our fortunate store of carbon and hydrogen, free and combined, and of uncombined oxygen. The known distances of the molecules of the gases above named under normal temperature and pressure give no clew to the