ASTRONOMY AND METEOROLOGY. 3-5 



eigh for the day when all these things shall be revealed, we must rest 

 on inference for the present, and remain content. 



But granting the existence of an ether of space, the question nat- 

 urally arises, What is its nature ? Is it matter ? And, if matter, is 

 it, as such, allied to any form of matter with which we are conver- 

 sant ? 



To answer this question we must begin by asking another, which 

 has, indeed, been put for us by Humboldt, and on the primary solu- 

 tion of which all our ability, all our possible reasons for the discov- 

 ery of the great and ultimate question, entirely turn. This prelim- 

 inary inquiry suggests, whether, if an ethereal fluid really exists in 

 space, it comes within our reach, whether, in other words, it com- 

 mingles, if the term is allowable, with our atmosphere, encircles our 

 bodies, penetrates matter, and, from the regions of the illimitable 

 space, extends into those infinitudes into which even the microscopic 

 eye has not as yet effectually penetrated ? This difficult problem is 

 well put by the great German philosopher : 



" The question of the existence of an ethereal fluid filling the 

 regions of space is closely connected with one warmly agitated by 

 Wollaston in reference to the definite limit of the atmosphere, a 

 limit which must naturally exist at the elevation where the specific 

 elasticity of the air is equipoised by the force of gravity. Faraday's 

 ingenious experiments on the limits of an atmosphere of mercury 

 (that is, the elevation at which mercurial vapors precipitated on gold 

 leaf cease perceptibly to rise in an. air-filled space), have given con- 

 siderable weight to the assumption of a definite surface of the atmos- 

 phere, similar to the surface of the sea. Can any gaseous particles 

 belonging to the region of space blend with our atmosphere, and pro- 

 duce meteorological changes ? Newton inclined to the idea that such 

 might be the case." 



But if the evidence be at all worth anything on which the hypoth- 

 esis of a universally diffused ether rests, then it must follow, of neces- 

 sity, in answer to the second question suggested, that the ether of 

 space does extend to the earth itself and to man himself. For if, 

 to take one example, it be true that light is due to the undulations of 

 the circumambient ether, then must the undulating medium be per- 

 sistent everywhere where light is demonstrable, so that we must 

 accept the idea of its presence immediately around us, in admitting 

 its presence altogether as a part of the universe. 



Here, however, speculation, we had almost said, ceases; at all 

 events, reasonable speculation, based on any sufficiency of data, here 

 abruptly ends. It must be confessed that no kind of physical 

 inquiry has led us by experiment to the recognition of any agent 

 constituting a part of the matter around us, to which the term ether, 

 used as regards the ether we are treating of, can be applied. If such 

 a body exists, it is beyond our estimation of all that is material. It 

 has no weight, according to our idea of weight ; no resistance, ac- 

 cording to our idea of calculating resistance by mechanical tests ; no 

 volume, on our views of volume ; no chemical activity, according to 

 our experimental and absolute knowledge of chemical action. In 

 plain terms it presents no known reagency by which it can be isolated 

 from surrounding or intervening matter, which is known. 

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