﻿Principles of Molecular Physics. 109 



by the motions of their own molecules " will hardly be accepted, 

 we think, by physicists. It would be a waste of time to argue 

 against it. 



Again, the notion that a certain substance radiates light of a 

 certain colour because its molecules are made to vibrate in unison 

 with the ray of that colour, will not stand ; for the results of 

 spectral analysis show that the parts of a body which are capable 

 by vibration of giving out any colour are precisely those which 

 absorb and stifle that colour. This fact, we may add, also proves 

 conclusively that the rays cannot be transmitted by the motion of 

 the molecules. Though so radically at variance with Professor 

 Bayma's theoretical views, it is in entire accordance with my 

 own ; for, according to these, light originates in certain vibratory 

 movements of the atoms of the electric atmospheres of molecules, 

 and when these vibrate naturally in unisou with the ray of any 

 colour that falls upon them, they take up its vis viva, and so the 

 ray is transformed into a molecular electric current. 



As to the "leading principles" laid down by the author, they 

 may in the main be conceded; but these by no means cover the 

 whole ground upon which his theory is raised. We find, for 

 example, that he assumes that all elements or material points of 

 the same form of matter act, under similar circumstances, with 

 the same intensity. Now if this principle be admitted, what 

 theoretical basis have we for the existence of distinct primitive 

 molecules for every different substance, the number of elements 

 associated together being exactly the same for each primitive 

 molecule of each substance, and different for primitive mole- 

 cules of different substances ? The natural tendency would be 

 to a fortuitous association of elements in an endless variety of 

 numbers into groups. No controlling principle by which uni- 

 formity would be evolved from chaotic confusion is furnished by 

 the theory. The Hand of the Creator must be supposed to have 

 miraculously interfered, and guided each element to its precise 

 place in the formation of every molecule of matter. The objec- 

 tion here urged derives still greater force from the consideration 

 that both the nucleus and envelope of each specific molecule are 

 assumed to have a regular geometrical form, different for each 

 substance. To assume the existence of such molecules is to 

 make an incalculable number of arbitrary assumptions. No 

 such exception can be taken to the views I have advocated ; 

 for primarily each specific atom of gross attractive matter must 

 appropriate to itself, from the universally diffused repulsive 

 aethers, its electric and its sethereal atmosphere, each of a certain 

 definite extent. Upon the relations of these specific atmospheres 

 to the central atom and to one another, all the different proper- 

 ties of each specific molecule must depend. 



