176 A MODEL OF MATURE. 



method of Sir W. Huggins, shows not only that the inner portions of 

 the ring move the more rapidly, but that the actual velocities of the 

 outer mid inner edges are in close accord with the theoretical velocities 

 of satellites at like distances from the planet. 



This and a hundred similar eases prove that it is possible to obtain 

 convincing evidence of the constitution of bodies between whose sepa 

 rale parts we can not directly distinguish, and 1 take it that a physicist 

 who believes in the reality of atoms thinks that he has as good reason 

 for dividing an apparently continuous gas into molecules as he has for 

 dividing the apparently continuous Saturnian rings into satellites. If 

 he is wrong it is not the fact that molecules and satellites alike can not 

 be handled and can not be seen as individuals that constitutes the dif- 

 ference between the two cases. 



It may, however, be urged that atoms and the ether are alleged to 

 have properties different from those of matter in bulk, of which alone 

 our senses take direct cognizance, and that therefore it is impossible to 

 prove their existence by evidence of the same cogency as that which 

 may prove the existence of a newly discovered variety of matter or of 

 a portion of matter too small or too distant to be seen. 



This point is so important that it requi res full discussion, but in deal- 

 ing with it. it is necessary to distinguish carefully between the validity 

 of the arguments which support the earlier and more fundamental 

 propositions of the theory and the evidence brought forward to jus- 

 tify mere speculative applications of its doctrines which might be 

 abandoned without discarding the theory itself. The proof of the 

 theory must be carried out step by step. 



The first step is concerned wholly with some of the most general 

 properties of matter', and consists in the proof that those properties 

 are either absolutely unintelligible, or that, in the case of matter of all 

 kinds, we are subject to an illusion similar to that, the results of which 

 we admit in the case of Saturn's rings, clouds, smoke, and a number 

 of similar instances. The believer in the atomic theory asserts that 

 matter exists in a particular state: that it consists of parts which are 

 separate and distinct the one from the other, and as such are capable 

 of independent movements. 



Up to this point no question arises as to whether the separate parts 

 are. like grains of sand, mere fragments of matter, or whether, though 

 they are the bricks of which matter is built, they have, as individuals, 

 properties different from those of masses of matter large enough to he 

 directly perceived. If they are mere fragments of ordinary matter, 

 they can not be used as aids in explaining those qualities of matter 

 which they themselves share. 



We can not explain things by things themselves. If it be true that 

 the properties of matter are the product of an underlying machinery, 

 that machinery can not itself have the properties which it produces, 



