On Gas Light. 369 



in aklliig this scheme, in procuring and distributing lights and to 

 apply it to the purposes of domestic oeconomy on a large scale, 

 for lighting houses, streets, and factories. 



The following remarks on the products of pit-coal, as far as 

 they relate to this new mode of procuring and distributing light, 

 it is therefore presumed, may be interesting to the public. The 

 statement is copied hterally from the printed evidence* given 

 by Mr. Accum, on the 10th" of May 1810, in the House of Lords, 

 when examined on that subject. 



*' Question. — Can you state in what proportion these results 

 are produced from a chaldron of coals ? 



^'Answer. — From reiterated experiments that I have lately 

 made I am enabled to say, that a hundred weight of Newcastle 

 coals produces from two hundred and fifty, to three hundred 

 cubic feet of gas ; and with regard to the light that is obtained 

 from the combustion of this quantity of gas 1 am enabled to state 

 that nineteen cubic feet of the gas, if applied to the purpose of 

 illumination, is equal to a pound of tallow candles ; that is to 

 say, if a tallow candle, six to the pound, be set up and lit, and 

 if it be suffered to burn for an hour and weighed after that time, 

 it will be found to have lost 180 grains; therefore 180 grains 

 of tallow are necessarily consumed in the combustion of a candle 

 during the time of one hour. — If I make a gas light of equal 

 intensity to that of the tallow candle, I find that half a cubic 

 foot of gas is requisite for the same period of time, and to give 

 the intensity of light ; therefore, from this statement it will be- 

 come obvious that nineteen cubic feet of gas are equal to on<i 

 pound of tallow candles, provided they were set up and burnt 

 out one after another, that is to say, nineteen cubic feet of gas^ 

 are demanded to give a quantity of light e([ual in duration of 

 time and in illuminating power to one pound of tallow candles, 

 six to the pound,— I have stated already that a hundredweight 

 of coal produces from 250 to 300 cul)ic feet of gas ; therefore 

 from this statement the valuta of gas light with regard to inten- 

 sity and duration of time may be learned when compared to that 

 of the light of candles. 



" A hundred jjounds of coal produces from four to five pounds 

 of tar upon an average; this tar is worth from 335. to 36f. 

 a barrel at presentf. — A chaldron of coals produces sixty 

 pounds of pitch, which is worth about three-pence halfpenny a 



* Minutes of Evidence taken before the Lords' Committees, to whom 

 was referred the Hill entituled, " An Act for cnablinK His Majesty to in- 

 corporate by Charter, a Company to be called The Gas Lii;ht and Coak 

 Company, for making inflammable Air for Lighting of the Streets of the 

 Metropolis," &c. Odered.to be printed May 22, 1810. 



t May 10, 1810. 



Vol. 44. No. 199. Nov. 1814. A a pound ; 



