FUEL 



III. Turf or peat. Ono pound of this fuel will heat, according to its quality, from 

 18 to 42 pounds of water from freezing to boiling. Its value depends upon its com- 

 pactness and freedom from earthy particles ; and its radiating power is to tho whole 

 heat it emits in burning as 1 to 3. 



According to Berthier, the following results were obtained from peat : 



Source of tho Peat. Pounds of water heated by 1 pound 



of peat from to 100 Cent. 

 . 18-1 

 . 27'9 

 . 29-2 

 . 34-9 

 . 34-6 



From Troyes . . . 

 department do la Somme 

 ,, de la Marne 



do la Vosges 



des Landes 



Winkler gives 26' 9 as the evaporative power of tho worst Hanoverian peat, and 

 42-6 as that of the best. 



Peat obtained from the Bog of Allen gave, according to Griffith (the discrepancies 

 between the results we do not understand) : 



Pounds of water heated from 

 to 100 Cent. 



Upper peat , 627 



Lower peat . 56 - 6 



Pressed peat 2S'0 



Soo PEAT. 



IV. Coal. Tho varieties of coal are almost indefinite, and give out very various 

 quantities of heat in their combustion. The carbon is the heat-giving constituent, 

 and it amounts, in different coals, to from 75 to 95 per cent. One pound of good coal 

 will, upon an average, heat 60 pounds of water from the freezing to the boiling point. 

 Small coal gives out three-fourths of the heat of the larger lumps. The radiating heat 

 emitted by burning pitcoal is greater than that by charcoal. 



V. The Coke of Coal. The heating power of good coke is to that of pitcoal as 75 

 to 69. One pound of the former will heat 65 pounds of water from 32 to 212 ; so 

 that its power is equal to nine-tenths of that of wood charcoal. 



Berthier gives as the results of his trials : 



Pounds of water heated by 1 pound 

 of coal from to 100 C. 



coal 72-0 



70-7 



70-0 



61-6 



(cannel) 53-2 



71-6 



65-6 



50-3 



Dowlais 

 Glamorgan 

 Newcastle 

 Derbyshire 

 Lancashire 

 Durham 



Coke (St. Etienne) ^ 

 Do. gas from Paris 



VI. Carburetted Hydrogen or Coal Gas. One pound of this gas, equal to about 24 

 cubic feet, disengages in burning as much heat as will raise 76 pounds of water from 

 the freezing to the boiling temperature. 



In the following table tho fourth column contains the weight of atmospheric air, 

 whose oxygen is required for the complete combustion of a pound of each particular 

 substance : 



Tho quantity of air stated in tho fourth column, is tho smallest possible required to 

 burn the combustible, and is greatly less than would bo necessary iu practic'.-, where 



