A Practical Manual On Sea Water Distillation
With A Description Of The Necessary Machinery For The Process

56 SEA WATER DISTILLATION. Welsh, and Scotch—conducted by Playfair and De La Beche, we are told that the average heat obtained amounted to 13,000 B.T.U. per lb. of coal. This is by calorimeter. 5. In a series of practical experiments made with the consumption of coal whilst working a boiler, conducted by H.M. Commissioners, some little while back, it was found as follows :— Lbs. of Water Kind of Coal. B.T.U. per lb. Vaporisable at Atmospheric Pressure at 212° Welsh, 8,800 9-0 Newcastle, .... 8,000 8-0 Lancashire, .... 7,700 8-0 Scotch, 7,450 7'7 Derbyshire, .... 7,400 7-5 Note.—All the above experiments appear to have been obtained whilst working with a small Cornish boiler of 7 H.P. With a boiler larger and more up-to-date the results would have been increased about 10 to 12 per cent. These different coals have been detailed here, because it will be found, when we come to the chapter on Multiple Distillation, that the quality of the fuel is a very important question. The opposite Table (G) gives the heating power of various descriptions of coal, and of other fuels, as compared with Welsh coal. Note.—Column (a) is approximate only, because the reports given of the heat obtained from fuels of the same description vary somewhat.