Energy and Ether. 1037 



146, 945 feet, and for hydrogen at 220c is 3, 126 feet \ The num- 

 ber of particles in all gases at the same pressure and temperature is pre- 

 cisely the same. The number in one cubic centimetre of air has been 

 estimated at twenty-one times the cube of a million (21,000,000,000,- 

 000,000,000). As the activities of the particles cause them to collide 

 with each other from four to ten thousand million times per second, the 

 average length of the path the}' traverse before they strike and rebound 

 from each other is very short, less than the ten-thousandth part of a milli- 

 metre ( 254 1 ooo of an inch). Knowing the number of molecules to a 

 given volume, it becomes possible to calculate the absolute weight of a 

 molecule, and this has been ascertained to be for hydrogen somewhere 



near i ooo ooo ooo 000-000 ooo ooo ooo of a gramme. 



The transportation of the energy by which these molecules are driven 

 and kept asunder, is by means of the ether. A hot body, as the sun, 

 communicates its motion to the ether, which delivers it to the molecules 

 of the gas. It must be therefore, that it is the ether among the mole- 

 cules which first receives the agitation, and whose consequent motion 

 compels that of the molecules themselves. It may be conceived, in 

 fact, that the undulations continue into and through the body of the 

 gas, and that the momentum of the energy thus communicated by these 

 undulations to the ponderable molecules keeps up the motion for a time 

 after the original energy has ceased to act. In a balloon of gas, subject 

 to an ordinary temperature, we may suppose the undulatory movements 

 to penetrate in all directions, and hence the motions of the molecules 

 to be in all directions as is required by the fact of the equal pressure of 

 the gas on all sides. 



We may suppose that the different selective affinities in chemical 

 combination are due to the agreements in the vibration of the ethers of 

 the bodies involved, the force of the attraction being greater in propor- 

 tion to the harmony of the vibrations. In the case of neutral bodies 

 we may suppose their ether is at rest, but from the shape of the body 

 it is connected with, it is endowed with a fundamental of its own which 

 causes it to become active when operated upon by a force of its own 

 pitch; and when thus active, an attraction occurs between it and the 

 body exciting its activity. In this respect as well as others the parallel 

 between chemism and magnetism is close. 



Catalysis or Contact Action of platinum and other substances was 

 mentioned on page 233. This action, which is due to the mere presence 

 of a third body that does not itself appear to undergo any change, pro- 

 motes a union which otherwise would be sluggish or impracticable. It is 

 usually explained that the presence of the third body, as the platinum, 

 causes the condensation of gases so that their particles are brought 



1 See Lothar Meyers' Outlines of Theoretical Chemistry p. 166. 



