.s/A' WILLIAM SIEMENS, F.R.S. 377 



the relative lii>i eost, and cost of working the secondary buttery 

 and i In engine respectively. These questions are, however, outside 

 the range of our present consideration. 



The large aggregate of dwellings comprising the metropolis of 

 London covers about seventy square miles, thirty of which may be 

 taken to consist of parks, squares, and sparsely inhabited areas, 

 which are not to be considered for our present purpose. The re- 

 maining forty square miles could be divided into say 140 districts, 

 slightly exceeding a quarter of a square mile on the average, but 

 containing each fully 3,000 houses, and a population similar to 

 that of St. James's. 



Assuming twenty of these districts to rank with the parish of 

 St. James's (after deducting the 600 shops which I did not include 

 in my estimate) as central districts, sixty to be residential districts, 

 and sixty to be comparatively poor neighbourhoods, and estimating 

 the illuminating power required for these three classes in the pro- 

 portion of 1 to to ^, we should find that the total capital 

 expenditure for supplying the metropolis with electric energy 

 to the extent of 25 per cent, of the total lighting requirements 

 would be 



20 x 177,000 = 3,540,000 



60 x i x 177,000 = 7,080,000 

 60 x \ x 177,000 == 3,540,000 





14,160,000 



or say 14,000,000, without including lamps and internal fittings, 

 and making an average capital expenditure of 100,000 per 

 district. 



To extend the same system over the towns of Great Britain and 

 Ireland would absorb a capital exceeding certainly 64,000,000, 

 to which must be added 16,000,000 for lamps and internal 

 fittings, making a total capital expenditure of 80,000,000. Some 

 of us may live to see this realised, but to find such an amount of 

 capital, and, what is more important, to find the manufacturing 

 appliances to produce Avork representing this value of machinery 

 and wire, must necessarily be the result of many years of technical 

 development. If, therefore, we see that electric companies apply 

 for provisional orders to supply electric energy, not only for every 



