Figures upon this point must necessarily be either averages or approximations. The nature of the locality socially, naturally, and we grieve to say it, politically, has a strong influence upon its construction. Estimating on single track only, a horse road would cost as an average $9,000 per mile. With electricity we have several methods we can avail ourselves of: Surface, costing about $10,000; overhead double conductor, $15.696; underground, $23,500. With cable but one method, the underground, is possible. This cost is variously estimated at from $30,000 to $110,000 per mile; however, the latter figure is excessive. A fair average would be $35,000. The ratio of constructions could be fairly placed as follows, putting electricity as 1, by taking the average of the three methods at $16,732: Horse road, 0.53; cable, 2.09. Unquestionably a great majority of roads of the past have not been constructions of engineering, and of all places requiring care, skill, and engineering, the street roads are the places. 5th. Cost of operation. A fair figure for cost of one horse for one year is $220. For electricity, allowing 35 per cent. loss in transmission, etc., 1.54 horsepower would be the work done by engine to get 1 horse power on the track. There are to-day plenty of steam plants producing 1 horse power for work at from $30 to $50 per annum. Take the average, $40. With electricity then $65 would well represent the price of producing 1.54 horsepower. With cable these figures would hold true, but more work is required. A greater loss is entailed. Since but 32 per cent. is recovered, the figure for 1 horse power on the track would be 2.86 horse power. At the above rates this would be $110 per horse power per year. Our ratio here is: Electricity, 1; cables, 1.71; horses, 3.38. This is by no means the whole of the story, for just here must we compute the depreciation and hence repairs due to time. Let us take the road figured on heretofore, and make three tables. In the following I have under each system taken the estimated costs, allowed a fair per cent. for depreciation, summed up and obtained the ratios. Any figure then like interest, etc., which would not affect ratios, I have omitted. ELECTRICITY. Conductors, 1 per cent. $160.00 Engine and dynamos, 5 per cent. 525.00 Cars, 10 per cent. 5,280.00 Roadway, 10 per cent. 2,007.00 ----------- Total. $7,972.00 HORSES. Horses and appurtenances, 20 per cent. $7,780.00 Cars, 10 per cent. 2,880.00 Roadway, etc., 10 per cent. 3,500.00 ----------- Total. $11,740.00 CABLES.