SPECULATIVE SCIENCE. \6i 



serve equally well to establish any other ratio, and who never thought 

 of asking himself the question whether or not a diameter 1 and a cir- 

 cumference 3^ were compatible whether or not his postulates were 

 consistent with each other is closely analogous to the mental pre- 

 dicament of certain scientific specialists who are constantly multiply- 

 ing forces, superable and insuperable, and all manner of entities^ with 

 impossible or contradictory properties, for the purpose of explaining 

 natural phenomena. When this is done with a proper insight into the 

 nature and use of such fictions with the understanding that they are 

 mere devices for fixing ideas or colligating facts (to use WhewelPs 

 expression) it is well enough. But, in many cases, the specialists have 

 no such insight. They begin to treat the fictions here spoken of as 

 undoubted realities, whose existence no one can question without sub- 

 jecting himself to a Newcombian fnstigation. Take the case of the 

 ether, the hypothetical substratum of luminar undulations. It is 

 first mentioned simply as a fluid of the greatest tenuity, as wholly 

 inappreciable to the senses, and as offering no resistance to atoms or 

 celestial spheres. Thereupon, to meet the exigencies of the undulatory 

 theory, it is endowed with a co-efficient of elasticity thousands of times 

 greater than that of steel. Next, at the demand of some physicist or 

 chemist, who wants to incase his atoms or molecules in ethereal at- 

 mospheres or envelopes, it is made as soft and mobile as hydrogen gas. 

 First, it is looked upon as continuous ; then, to explain the dispersion 

 of light, it is made discontinuous, and "finite intervals" are interposed 

 between its atoms. But now comes Clerk Maxwell, and shows that, 

 if the constitution of the ether were atomic, consequences would ensue 

 upsetting the whole theory of heat ; or Helmholtz and Sir William 

 Thomson, in order to be able to construct their vortex-atoms, require 

 it to be absolutely frictionless and incompressible, and therefore con- 

 tinuous ; and, accordingly, it is restored again to its ancient continuity, 

 no matter what may become of Cauchy's theory of chromatic dispersion 

 or Fresnel's theory of polarization. Originally there is but one ether ; 

 but presently Professor Norton contends that the luminiferous ether 

 is not available for the purpose of explaining the phenomena of elec- 

 tricity and magnetism. He demands a second ether, filling the same 

 space with the first ; and his demand is complied with. In a 6hort 

 time Mr. Hudson appears with the claim that even the phenomena 

 of light can not be accounted for on the supposition of a single 

 light-bearing ether ; and he must have two luminiferous media, " each 

 possessed of equal and enormous self - repulsion or elasticity, and 

 both existing in equal quantities throughout space, whose vibrations 

 take place in perpendicular planes ; the two media being mutually in- 

 different, neither attracting nor repelling " and, again, his request is 

 granted without further ceremony. To cap the climax, finally arrives 

 the pangeometer, and insists that back of and behind all these ethers 

 there is an independently real thing, an object of direct sensation, 

 TOL. xxi. 11 



