The posts and supports to be provided and fixed by the company, or, if the town council found the same, the company would allow a deduction at the rate of 5 per cent. per annum upon the outlay made by the council. The lamps are usually about 400 feet apart. The actual cost of operating arc lights on this system is given in the following detailed expenses of a six hours’ run of a 50-light plant for the street lighting of an American city:— 2,600 lb. Ind. nut and slack coal, at $1·30 per ton $1·69 Engineer, one night, at $50·00 per month 1·67 Superintendent or electrician, one night, at $50·00 per month 1·67 Trimmer, one day, at $40·00 per month 1·33 48 pairs of carbons, at $18·50 per month 89 Waste, &c., at $20·00 per year 05 Water rent, at $40·00 per year 11 Half-pint cylinder oil, at 60c. per gallon 04 One pint engine and dynamo oil, at 50c. per gallon 06 One day repairs on machine and lamps, including globes, at $120·00 per year 33 One day taxes on 50-light plant, assessed at $5,000, at 2¼ per cent. 31 One day interest on 50-light plant ($10,000), at 6 per cent. 1·67 ————— Making a total of $9·82 10½_d._ or 20·45 cents. per lamp. £15 10_s._ per annum. If, in addition to the 50 street lights, 33 other arc lights are maintained, the total cost is reduced for a six hours’ run to $13·25, or £2 15_s._ 2_d._ for the 83 lights, 8_d._ or 15·96 cents per lamp, £12 3_s._ 4_d._ per annum. Table V. has been calculated by M. Decker, of Nuremburg, and gives the comparative cost of working 150 lamps by electricity and by gas. The gas price (1) is that paid in Paris, namely, 6_s._ 9_d._ per 1000 cubic feet; column (2) is the price usually taken commercially, which includes the fixed charges. The price of electricity is given: 1st, when a steam-engine is available; 2nd, when it is necessary to lay down a special engine; 3rd, when a gas-engine is used the gas is charged at a trifle over the price in column (1). TABLE V. _Total Cost per Hour and per Lamp._ Legend for Table V. A = Number of hours’ work per year. B = Number of hours’ work per day. C = Steam-engine (existing). D = Hydraulic Motor. E = Steam-engine to be erected. F = Gas engine G = (1) Gas at 6_s._ 9_d._ per 1,000 ft. H = (2) Gas at 8_s._ 9_d._ per 1,000 ft.