ELECTRIC AND GAS ILLUMINATION. 585 



Under this last heading there should be added rent and taxes, man- 

 agement, law charges, bad debts, and various incidentals. These can 

 not be separately arrived at with any closeness, but they may be taken 

 in the lump as about the same part of the total charges as in the 

 case of the London companies, which is 16 per cent, exclusive of the 

 interest on investment. This in the present case would be 9*4 cents 

 per 1,000, bringing the total cost per 1,000 up to 71 cents with gas and 

 60 cents with electricity. 



The promoters of the electric light would probably demur to this 

 statement, so far as rent and taxes are concerned, as they insist upon 

 the much smaller real estate required with the electric than with a gas 

 plant. This difference does not, however, seem to me sufficient to be 

 of any practical moment, as the real estate in the case of electricity is 

 in the district supplied, where the price of land is relatively high, 

 while the gas companies can readily place their works in such locality 

 as to compensate in lowered land value for the greater amount re- 

 quired. Gas companies can, moreover, build within much smaller 

 limits than usual when for any reason it is desirable, and closely ap- 

 proach the space requisite for an electric installation. 



An item of considerable amount which has been omitted from the 

 estimate for electricity is the cost of the renewal of the lamps. "With 

 the general introduction of incandescent electric lighting, this is a 

 charge which would fall directly upon the consumer, but it is one 

 which would steadily diminish with improvement in lamps. Assum- 

 ing, however, that it is a legitimate charge upon the company supply- 

 ing the light, the item amounts to 10 cents per 1,000, if the lamps have 

 a life of 600* hours and cost 30 cents. This brings the electric ac- 

 count up to 70 cents per 1,000. 



So far as coal-gas is concerned, then, these figures show a slight ad- 

 vantage in favor of electricity, and while they are only approximative 

 they are near enough to the truth, I think, to represent the actual 

 relation of the two illuminants. "While very much doubtless remains 

 to be done in the improvement of coal-gas manufacture, it does not 

 seem probable that this will affect its cost of production to the same 

 extent as future improvements of electric apparatus may be expected 

 to decrease that of the electric light. Looking closely at the two ac- 

 counts, it does not seem probable that the item relative to plant will be 

 materially lessened in the future. The cost of the plant has already 

 been taken at a figure very near the lower limit, so near that the sub- 

 stitution of this in its place would make a difference in the yearly 

 plant account of but 2-J cents per 1,000. We may, on the other hand, 

 expect improvements to largely reduce the cost of the electric plant. 

 On Mr. Edison's system of distribution, the size of the conductors 

 varies inversely as the resistance of the lamps, so that they may be 



* I am informed by Mf . Edison that the average life of the lamps is now 900 hours, 

 including 3 per cent breakage in handling. 



