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

FUELS. 57 TABLE G.—Welsh Coal compared with other Combustibles. Col. (a) — Comparative Heating Power of various fuels. „ (6) — Comparative Weights of fuel to give the same heat. Description of Fuel. (a). (&). 1 Welsh coal, 1-000 1’000 Newcastle coal, 0-916 1091 Derbyshire coal, 0-9 1-111 Lancashire coal, 0-9 1111 1 Scotch coal 0-913 1-095 Yorkshire coal, 0'915 ro9i Coke, 0-71 1-408 Charcoal, 0'779 1-285 Patent fuel, 1-5 0-83 Wood (dry and hard), 0’42 2'381 Petroleum, 1-29 0-775 Alcohol (spirits of wine), .... 0-97 1-032 Town gas (30 cf. = 1 lb.), . 1-385 0-7 Note.—One ton of coal produces 1 chaldron of coke ; and approximately 1 ton equals 1| chaldrons. One ton of loose coal averages about 45 cubic feet, and a chaldron of coke averages 75 cubic feet. (J) Patent Fuels. 6. Besides coal, there are various mixtures of coal dust with coal tar, &c., known as patent fuels. The heating power of these mixtures varies a good deal, much de- pending upon the class of coal used in the mixture. These fuels are usually in the shape of briquettes, which can be broken up and used as required. (c) Wood and (d) Petroleum. 7. It is not uncommon to have boilers fired with wood or petroleum, especially abroad, where coal is more costly. The Table (G) just given, shows that wood is consider-