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THE POPULAR SCIENCE MONTHLY. 



forever in the memory. The exquisite delight we experience in listen- 

 ing to the works of our great composers arises thus in mechanical 

 movements, which are the issue of mathematical combinations. The 

 flnseen world is under the influence of number ! 



But what is number except there be one who numbers ? When 

 Pompey, in his Syrian war, broke into the holy of holies at Jerusalem, 

 he expressed, as Tacitus tells us, his astonishment that there was no 

 image of a divinity within; the shrine was silent and empty. And 

 so, though after death we may anatomize and explore the inmost re- 

 cesses of the brain, the veiled Genius that once presided there has 

 eluded us, and has not left so much as a phantom-trace, a shadow of 

 himself. 



The experiments of Galvani and Volta have not yet reached their 

 conclusion ; those of Faraday and Du Bois-Reymond have only yielded 

 a preliminary suggestion as to the nervous force. Excepting the 

 great sympathetic nerve, the nervous fibres themselves are, as is well 

 known, of two classes those that gather the impressions of external 

 things and convey them to the nerve-centres, and those that transmit 

 the dictates of the will from within outwardly. The capabilities of 

 one of the former the apparatus for sight have been greatly im- 

 proved by various optical contrivances, such as microscopes and tele- 

 scopes, an earnest of what may hereafter be done as respects the four 

 other special organs of sense ; and, as concerns the second class, the 

 result of mental operations, the resolves of the will, may be transmit- 

 ted with greater velocity than even in the living system itself, and 

 that across vast terrestrial distances, or even beneath the sea. Tele- 

 graphic wires are, strictly speaking, continuations of the centrifugal 

 nerves, and we are not without reason for believing that it is the same 

 influence which is active in both cases. 



In a scientific point of view, such improvements in the capabilities 

 of the organs for receiving external impressions, such extensions to 

 the distances to which the results of intellectual acts and the dictates 

 of the will may be conveyed, constitute a true development, an evo- 

 lution, none the less real though it may be of an artificial kind. If 

 we reflect carefully on these things, bearing in mind what is now 

 known of the course of development in the animal series, we shall not 

 fail to remark what a singular interest gathers round these artificial 

 developments artificial they can scarcely be called, since they them- 

 selves have arisen interiorly. They are the result of intellectual acts. 

 Man has been developing himself. He, so far as the earth is con- 

 cerned, is becoming omnipresent. The electrical nerves of society are 

 spread in a plexus all over Europe and America ; their commissural 

 strands run under the Atlantic and the Pacific. 



In many of the addresses that have been made during the past 

 -summer, on the Centennial occasion, the shortcomings of the United 



