Correspondence.

Feilding Star, Volume XVII, Issue 287, 10 June 1896, Page 2

Correspondence.

THE ELECTRIC QUESTION. TO THE EDITOR. ... Sir, — I was very much interested in Dr Monckton's letter that appeared in your issue of the 4th instant on acetylene gas as an illuminant. As the writer implied it was a cheaper light than that produced by electricity, I will, with your permission, compare the cost of these two lights. On March 20th, 1895, Mr T. L. Wilson, maker of the first "calcium carbide " by the electric furnace process, read a paper at a meeting of the Franklin Institute, Philadelphia, wherein he stated that acetylene gas, when burned at the rate of 5 cubic feet per hour— 5 cubic feet per hour being the standard for computing candle power— produced a light equal to 250 candles. Philadelphia gas ranges from 19 to 20 candle power. Mr Wilson's company was then making one ton of calcium carbide per day. They found that one electric horse power could produce 201bs of calcium carbide each 24 hours, and they hoped that with automatically- fed furnaces, properly insulated, to retain the' heat', and by utilising the . waste heat to increase the temperature of the material acted upon, the production of calcium carbide could, on a large scale, be increased to 801bs per electrical h.p. each 24 hours, the amount per h.p. each hour being lib of the calcium carbide. Now, the theoritically possible value of lib, of carbide is 5*89 cubic feet of gas, and the best actual resnlt 5*75 cubic feet of gas, equal to, say, 288 candles, for which one h.p. has been expended. ; The electrical horse power is 746 watts, and large incandescent lamps show a consumption of 24 watts per caudle. This is over 800 candle power per h.p. In axe lights from 700 to 1000 candle power can be obtained from one horse power, showing that the same amount of electrical energy if applied direct to the production of light Will give three times as much light than if making calcium carbide for the supply of acetylene gas. I am, &c., C. H. HoskinOj