800 THE POPULAR SCIENCE MONTHLY. 



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 exist- 

 ed 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 moun- 

 tain-climber for a whole day. An apparently inert explosive is trav- 

 ersed 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 lib- 

 erated, 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 in- 

 telligible 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 character- 

 istic, 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 pro- 

 vided. Until very recently, no means were contrivable for subduing 

 the elementary gases, but, by resorting to the most extraordinary com- 

 pression, in conjunction with the lowest temperature procurable by 

 artificial means, the feat has been accomplished. There is a way, how- 

 ever, of pitting certain elements against each other by taking advan- 

 tage 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 



