1882.] on Electric Lighting hij Incandescence. 41 



manual labour is concerned, not very unlike the stoking of a steam 

 boiler, and if electricity is generated by means of steam, then the 

 manual labour chiefly involved in both processes is not unlike. It is 

 evident that in gas manufacture it would be necessary to shovel into 

 the furnaces and retorts five or six times as much coal to yield the 

 same light product as would be obtainable through the steam engine 

 and incandescent lamps. But here again it is necessary to allow for 

 the value of the labour in connection with the products other than 

 gas, and hence it is right to cut down the difference I have mentioned 

 to half — i.e. debit gas with only half the cost of manufacture, in the 

 same way as in our calculation we have charged gas with only one- 

 half the coal actually used. But when that is done, there is still a 

 difference of probably three to one in respect of labour in favour of 

 electric lighting. 



I have made these large allowances of material and labour in 

 favour of the cost of gas, but it is well known that the bye products 

 are but rarely of the value I have assumed. I desire, however, to 

 allow all that can be claimed for gas. 



With regard to the cost of plant, I think there will be a more 

 even balance in the two cases. In a gasworks you have retorts and 

 furnaces, purifying chambers and gasometers, engines, boilers, and 

 appliances for distributing the gas and regulating its pressure. Plant 

 for generating electricity on a large scale would consist principally 

 of boilers, steam engines, dynamo-electric machines, and batteries for 

 storage. 



No such electrical station, on the scale and in the complete form 

 I am supposing, has yet been put into actual operation ; but several 

 small stations for the manufacture of electricity already exist in 

 England, and a large station designed by Mr. Edison is, if I am 

 rightly informed, almost comj)leted in America. We are therefore 

 on the point of ascertaining by actual experience, what the cost of 

 the loorJcs for generating electricity will be. Meanwhile, we know 

 precisely the cost of boilers and engines, and we know approximately 

 what ought to be the cost of dynamo-electric machines of suitably 

 large size. We have, therefore, sufficient grounds for concluding 

 that to produce a given quantity of light electrically the cost of 

 plant would not exceed greatly, if at all, the cost of equivalent gas 

 plant. 



There remains to be considered, in connection wdth this part of 

 the subject, the cost of distribution. Can electricity be distributed as 

 widely and cheaj)ly as gas ? On one condition, which I fully hope 

 can be complied with, this may be answered in the affirmative. The 

 condition is that it be found practicable and safe to distribute 

 electricity of comparatively high tension. 



The importance of this condition will be understood when it is 

 remembered that to effectively utilise electricity in the production of 

 light in the manner I have been explaining, it is necessary that the 

 resistance in the carhon of the lamps should be relatively great to the 



