84 CALORIFIC POWER OF FUELS. 



So that the amount of combustible matter does not increase 

 after 5 hours' heating, and a continuance of the heat diminishes 

 it. 



The principal use of charcoal is in iron furnaces, where it 

 has been used for years, and produces the highest grades of 

 iron, being free from sulphur and phosphorus. A small 

 amount is used in private dwellings and hotels for heating 

 and cooking. For boiler heating it has been used only 

 experimentally. 



Scheurer-Kestner and Meunier-Dollfus experimented with 

 it in boiler-heating and found very little combustible gas in 

 the products. Beech charcoal was used, and an evaporative 

 effect of 7.62 pounds of water was obtained. The waste 

 gases contained : 



Carbonic acid , 11.16 per cent. 



Carbonic oxide O-37 " 



Oxygen 8.72 " 



Nitrogen , 79-75 " 



100.00 



Bnx, using wood and peat charcoal, obtained the follow- 

 ing results : 



Wood charcoal 7.55 pounds evaporated. 



Peat charcoal 6.85 



Schwackhofer burnt charcoal from hard and soft wood in 

 his calorimeter and obtained (constant volume) 7140 calories 

 for the soft charcoal and 7071 calories for the hard. The 

 charcoal in both cases was the ordinary unpurified charcoal as 

 sold. 



WOOD. 



Wood consists of a compact tissue more or less hard, 

 formed of cellulose and a so-called incrusting substance. 



