S/X WILLIAM SIEMENS, F.R.S. 379 



that, electric light by incandescence, when carried out on a large 

 scale, is decidedly cheaper than gas lighting at present prices, and 

 with the ordinary gas burners. 



On the other hand, the cost of establishing gas works and mains 

 of a capacity equal to 64,000 argand burners, would involve an 

 c \prnditure not exceeding 80,000 as compared with 177,000 

 in the case of electricity ; and it is thus shown that, although it 

 is more costly to establish a given supply of illuminating power by 

 electricity than gas, the former has the advantage as regards 

 current cost of production. 



It would not be safe, however, for the advocates of electric 

 lighting to rely upon these figures as representing a permanent 

 state of things. In calculating the cost of electric light, I have 

 only allowed for depreciation and 5 per cent, interest upon capital 

 expenditure, whereas gas companies are in the habit of dividing 

 large dividends, and can afford to supply gas at a cheaper rate, by 

 taking advantage of recent improvements in manufacturing opera- 

 tions, and of the ever-increasing value of their by-products, 

 including tar, coke, and ammoniacal liquor. Burners have, more- 

 over, been recently devised by which the luminous effect for a 

 given expenditure of gas can be nearly doubled by purely me- 

 chanical arrangements, and the brilliancy of the light can be 

 greatly improved. 



On the other hand, electric lighting also may certainly be 

 cheapened by resorting, to a greater extent than has been assumed, 

 to arc lighting, which, though less agreeable than the incandescence 

 (or glow) light for domestic purposes, can be produced at less than 

 half the cost, and deserves on that account the preference for 

 street lighting, and for large halls, in combination with incan- 

 descence lights. Lamps by incandescence may be produced 

 hereafter at a lower cost, and of a more enduring character. 



Considering the increasing public demand for improved illumina- 

 tion, it is not unreasonable to expect that the introduction of the 

 electric light to the full extent here contemplated, would go hand- 

 in-hand with an increasing consumption of gas for illuminating 

 and for heating purposes, and the neck-to-neck competition be- 

 tween the representatives of the two systems of illumination which 

 is likely to ensue, cannot fail to improve the quality, and to cheapen 

 the supply of both, a competition which the consuming public can, 



