TECHNOLOGY. 399 



use promises to become almost universal. Experiment has 

 shown that the Bell telephone can transmit articulate speech 

 through a resistance equal to five hundred and fifty miles of 

 telegraph wire. In practice, however, it has not been found 

 possible to speak through this distance, partly from loss of 

 current by interference of induced currents from other wires, 

 and partly on account of loss by leakage. It is impossible 

 to say to what degree of perfection the instrument may not 

 be brought by subsequent improvements. 



THE PHONOGRAPH. 



An apparatus which shall make a permanent graphical 

 record of spoken words or musical sounds, and by means of 

 which we may be able, at any future time, to reproduce, in 

 audible form, the same sounds it has recorded, and with all 

 the peculiarities of pronunciation and inflection in other 

 words, a veritable talking-machine has been successfully 

 realized in practice by Mr. T. A. Edison, who has styled it 

 the phonograph. Although as yet imperfect, it is neverthe- 

 less sufficiently practical to prove beyond doubt the practi- 

 cability of a talking-machine that will store up sounds indef- 

 initely and reproduce them at pleasure. To venture an opin- 

 ion of its possible utility at this time would be premature. 



ELECTRIC LIGHTING. 



During the past year considerable attention has been di- 

 rected towards the subject of electric lighting. The inter- 

 est developed was mainly due to certain inventions of M. 

 JablochkofF, who has succeeded in producing a very much 

 simplified form of lamp, by means of which, without the ne- 

 cessity of employing clock-work or other mechanical arti- 

 fices, it is rendered possible to work a number of lights inde- 

 pendently on the same circuit, so that an accident to or the 

 extinction of one lamp will not affect the others. 



The device above alluded to, known popularly as "The 

 J ablochkoff Electric Candle," consists essentially of two rods 

 of gas carbon, held side by side by a holder of asbestos, but 

 kept slightly apart by the interposition of a slender rod of 

 some insulating material (kaolin, glass, etc.). The carbons 

 are held in tubes of copper, and copper wires in connection 

 with these conduct the current from the dynamo -electric 



