344 ELECTRICITY DURING THE NINETEENTH CENTURY. 



they are numbered b}^ hundreds of thousands. The annua] consump- 

 tion of carbons in this country has reached 200,00(),0()0. 



Almost simultaneously with th(» beginning of the commercial work 

 of arc lighting, Edison, in a successful effort to provide a small electric 

 lamp for general distribution in place of gas, brought to public notice 

 his carbon filament incandescent lamp. 



A considerable amount of progress had previousl}^ been made by 

 various workers in attempting to reduce the volume of light in each 

 lamp and increase the number of lights for a given power expended. 

 Forms of incandescent arc lamps or semiincandescent lamps were tried 

 on a considerable scale abroad, but none have survived. So, also, many 

 attempts to produce a lamp giving light by pure incandescence of solid 

 conductors proved for the most part abortive. Edison himself worked 

 for nearly two years on a lump ])ased upon the old idea of incandescent 

 platinum strips or wires, but without success. The announcement of 

 this lamp caused a heavy drop in gas shares long before the problem 

 was really solved by a masterly stroke in his carbon filament lamp. 

 Curiouslv, the nearest approach to the carbon filament lamp had been 

 made in 1845 by Starr, an American, who described in a British patent 

 specification a lamp in which electi'ic current passed through a thin 

 strip of carbon, kept it heated white when sui'rounded by a glass bulb 

 in which a vacuum was maintained. Starr had exhibited his lamps to 

 Faraday in England and was preparing to construct dynamos to fur- 

 nish electric current for them in place of batteries, but sudden death 

 put an end to his labors. The specification describing his lamp is per- 

 haps the earliest description of an incandescent lamp of any promise, 

 and the subsequently recorded ideas of inventors up to the work of 

 Edison seem now almost in the nature of retrograde movements. 

 None of them was successful commercially. Starr, who was only 25 

 years of age, is reported to have died of overwork and worry in his 

 efforts to perfect his invention. His ideas were evidently far in 

 advance of his time. 



The Edison lamp differed from those which preceded it in the ex- 

 tremeh" small section of the carbon strip rendered hot b^^ the current 

 and in the perfection of the vacuum in which it was mounted. The 

 filament was first made of carbonized paper and afterwards of bamboo 

 carbon. The modern incandescent lamp has for years past been pro- 

 vided with a filament made by a chemical process. The carbon formed 

 is exceedingh^ homogeneous and of uniform electric resistance. Edison 

 first exhibited his lamp in his laboratory at Menlopark, N. J., in 

 December, 1879, but before it could be properly utilized an enormous 

 amount of work had to be done. His task was not merely the improve- 

 ment of an art already existing, it was the creation of a new art. 

 Special dj'namo machines had to he invented and constructed for work- 

 ing the lamps, switches were needed for connecting and disconnecting 



