Intelligence and Miscellaneous Articles. 443 



It is not at all as if those molecules were moving in empty space. 

 A molecule, if assumed to acquire an infinite velocity, would 

 certainly have to be assumed to possess an infinite energy. It may 

 be questioned whether even the total energy of translatory motion 

 of the stars in the collective universe is infinite in sum ; if 

 not, then a single molecule with a supposed infinite velocity 

 would require to have a greater total energy than this. The 

 expression " infinite velocity " apparently only comes into the 

 mathematical calculations applicable to a gas, supposed infinite in 

 extent. But in these calculations it seems tacitly to be supposed 

 that the molecules are moving in empty space, which is, however, 

 not a fact. On the contrary*, the molecules move in a resisting 

 substance whose obstruction to motion increases in a high ratio 

 with the velocity of the bodies which traverse the resisting 

 substance. 



Hamburg, March 1891. 



THE LIGHTNING DISCHARGE. BY S. TOLVER PRESTON. 



Prof. Colladon has stated from personal observation (' Nature,' 

 July 1, 1880) that trees struck by lightning give indication of a 



* The late Prof. Clerk Maxwell arrived at some data as to the size &c. 

 of molecules. If we assume a hydrogen molecule to vibrate through an 

 amplitude (say) two thirds of its diameter at a certain temperature, we 

 can obviously get the total distance traversed through the aether in one 

 second by the molecule through its vibrations, i. e. the total distance the 

 molecule would have traversed if, instead of oscillating it had moved 

 through the same total distance per second in a straight line. I find this 

 distance to be about ninety miles, i. e. the molecule vibrates at the rate of 

 ninety miles per second, by the above assumed amplitude of vibration in 

 terms of dimensions of molecule (which seems quite possible). According 

 to Maxwell, two million hydrogen molecules placed in a row woidd 

 occupy a millimetre. Hence it appears practicable that molecules can 

 vibrate at a greater rate than a planetar}'- velocity, which may seem 

 surprising to some, considering how small the dimensions of molecules are 

 (and therefore their amplitudes of movement). The velocity of the earth in 

 its orbit, for instance, is eighteen miles per second, as is known. The above 

 comparatively high estimate for vibratory velocity of molecules (ninety 

 miles per second, only a rough estimate of course) may account rationally 

 for the energy contained in the heat-waves of gases and other bodies, 

 which (energy) is a measure of the friction or resistance opposed by the 

 aether to the vibration or movement of a body in it. Calculations of this 

 kind, although of course only approximate, may give us conceptions or ideas 

 of the aether structure. If I had by me data as to the energy of the waves 

 emitted by a gas (radiating power), it would obviously not be difficult to 

 compute the static resistance opposed by the aether to the vibratory move- 

 ment or swing ot the molecule in it, in terms of the weight of the mole- 

 cule, i. e. in terms of gravity. Whether we have here a swing of the 

 molecule, a movement of rotation oscillatoiy in its nature, or any move- 

 ment of a repeated kind, the same considerations evidently in principle 

 apply. 



