August 21, 1885.] 



SCIUNCE. 



147 



tomatic, acoustic, duplex, quadruplex, sextu- 

 plex, printing, fire-alarm, district, and domes- 

 tic ; about the same number have reference 

 to electric-lighting ; while the remainder refer 

 to the telephone, the electric transmission of 

 power, the electric pen, and other miscellane- 

 ous inventions. Among all these, perhaps the 

 most remarkable are the quadruplex telegraph, 

 by which two messages ma}' be sent simulta- 

 neoush' in opposite directions from each end 

 of the line ; the automatic telegraph, which 

 can transmit a thousand words a minute ; the 

 motograph relay ; the carbon telephone ; the 

 Edison S3'stem of electric-lighting b}" incandes- 

 cence ; and the Edison electric railwa3\ 



Besides his inventive talent, Edison pos- 

 sesses marked abiUt}' as an investigator. He 

 discovered indepenclentl}^ the variation in re- 

 sistance produced in semi-conductors by press- 

 ure ; utilizing afterward this fact in the 

 construction of his transmitting telephone, his 

 tasimeter, and his telephone relay. He first 

 observed the curious fact that the passage of 

 an electric current between a metallic and a 

 moist semi-conducting surface varies the fric- 

 tion between these surfaces, — a phenomenon 

 supposed at first to be electrolytic, though now 

 believed to be electro- capillary. This fact he 

 at once applied to practical use in the moto- 

 graph relay and the loud-speaking telephone. 

 While experimenting with platinum for the 

 purposes of electric-lighting, he observed that 

 this metal occluded an enormous amount of 

 gas, and noted the remarkable fact that the 

 fusing-point of the metal rose as this gas was 

 expelled ; so that a platinum coil, after long- 

 continued treatment at a high temperature in a 

 vacuum, could be made to give man}' tinies as 

 much light as a coil of the untreated metal. 

 Hence he propounded the theory that the an- 

 nealing process consists in the expulsion of 

 the occluded gases by heat, thus leaving the 

 metal more or less porous, and therefore soft 

 and flexible. The various phenomena which 

 he has obser\'ed in his incandescent lamps are 

 of great scientific interest. In the first place, 

 these lamps are of exceptional efficiency as 

 condensers. In the second, the Crookes effect 

 is very marked in them, and is equally curi- 

 ous, whether we explain it on Edlund's as- 

 sumption that a vacuum is a conductor, or on 

 the more probable hypothesis of Rowland, 

 electrical transference by convection. More 

 surprising still, perhaps, is the fact of the 

 ready passage of the current through the glass 

 of these lamps, as proved by him, even at the 

 base, where the glass is not heated. 



Of all his discoveries, however, that of the 



phonograph has undoubtedly given him the 

 widest general reputation. The extreme sim- 

 plicity of the apparatus by which the tones of 

 the human voice could be recorded, and after- 

 wards faithfully reproduced, excited great in- 

 terest, not only among the masses, but also in 

 scientific circles, since it promised to be a 

 valuable instrument for the investigation of 

 articulate speech. His latest contribution to 

 science, a photometer containing an accurate 

 standard of light, bids fair to add equally to his 

 well-earned reputation. These facts, among 

 others that might be mentioned, are quite suffi- 

 cient to show Edison's acuteness as an original 

 observer, and to establish his capability in the 

 direction of independent research. It is much 

 to be regretted that want of time, and a de- 

 cided distaste for the manual labor of putting 

 his thoughts upon paper, has prevented him 

 hitherto from placing his discoveries on perma- 

 nent record. 



The exhibit made by Edison in 1881 at the 

 Electrical exhibition in Paris was a most 

 interesting one. On both sides of the ocean 

 he had been severely criticised, and often 

 abused, for views held to be chimerical and 

 absurd. At very considerable trouble and 

 expense, therefore, he prepared an elaborate 

 collection of apparatus illustrating his inven- 

 tions, including many articles of great historic 

 value, and sent them to Paris, in order, as he 

 said, to prove whether or not he had made 

 original discoveries and inventions. The ex- 

 treme ingenuity of these devices, the thorough 

 knowledge of scientific principles everywhere 

 shown in them, and the great electrical and 

 mechanical skill evident in their construction, 

 won for him, unsolicited, the most complimen- 

 tary encomiums, and secured without oppo- 

 sition the highest award within the gift of the 



jury. 



In person, Edison is of medium height, 

 rather stout, and quite informal in manner. 

 His face is clean-shaven ; his hair dark, with 

 here and there a tinge of gray ; and his eyes 

 brown, deep-set, but sharp and clear. A 

 slight deafness gives him a rather absent, and 

 sometimes listless air, which disappears at 

 once, as soon as he becomes interested in 

 conversation. In his experimentation he is 

 minute and painstaking, noting carefully the 

 phenomena he is investigating, and recording 

 accurately the results. Moreover, he is not 

 only quick to observe facts, but prompt to 

 detect their practical importance, and ready 

 to seize upon such of them as may serve as 

 the basis of an invention. His mode of living 

 is extremely simple. In his manners and way 



