268 APPLIED SCIENCE 



working days in the year, the sum of 455Z. gives \l. 10s. 4d. per 

 diem, and the 600th part of this is about 0'61 of a penny as the 

 cost of the power required to carry a ton one mile. In Great 

 Britain we ought easily to be able to reduce this below a half- 

 penny per ton per mile, which proves that the apparent great 

 waste, even of two-thirds of the power in transmission, does not 

 involve prohibitory expense. In calculating the whole cost of 

 transport, we must further take into consideration the cost of 

 installation. Taking the spans at 70 feet, I estimate this cost 

 as follows : 



Line 500?. per mile 2,500 



Engine, boiler, and shed, at 201. per indicated horse-power 1,400 



Dynamo and fittings ....... 1,000 



Twenty-five trains ........ 2,500 



Contingencies ......... 600 



Total cost 



Allowing 12^- per cent, for interest and depreciation, this repre- 

 sents an annual cost of 1,000^. Allowing 100Z. as the salary of 

 an electrician or young engineer, and adding 455Z. as the cost of 

 the power, this gives a total annual expenditure of 1,555?. for a 

 daily duty of 600 ton-miles. If we continue to assume the year 

 as containing 300 working days, the total cost of conveying one 

 ton one mile will be found equal to 2'07<i. If goods are to be 

 transmitted for long distances, the same calculation applies. We 

 should simply have stations ten miles apart, working lines five 

 miles long on each side of them. This, then, is the practical out- 

 come of the general principles stated at the beginning of this 

 paper. We may expect with great confidence that it will pay 

 investors to convey goods for any distance at the rate of 2d. 

 per ton per mile, by the agency of the suspended telpher line. 



Second Line. Matters are somewhat modified when the traffic 

 is smaller. Making similar calculations for a line one mile long 

 instead of five, with only four trains running at once, we might 

 employ an electromotive force as low as 100 volts; the loss by 

 heating would be insignificant ; we should require about 12 horse- 

 power ; the work done in eight hours would be 96 ton-miles. 

 I estimate the cost of installation at 1,600Z., and the annual cost 

 of working 344Z. without the annual salary of an electrician. 



