330 



BUTTER-MAKING. 



from chimneys is partially wasted coal. If the grates are 

 choked with a thick fire, no air can pass through, and the 

 volatile parts of coal pass off without being burned. 



Burning Wood or Coal. In some localities this question is 

 of minor importance, as conditions may be such that coal 

 only can be used. In other sections, where both are obtain- 

 able, it is of great importance. The following table* shows 

 figures obtained at five factories in Wisconsin where soft coal 

 was burned and five others where wood was used. 



DAILY FUEL USED AT SEVERAL CREAMERIES. 



These are the best obtainable figures of comparison under 

 creamery conditions. 



In connection with burning wood the dryness of it is an 

 important consideration. If the wood is wet its power of 

 producing heat is greatly lessened. A certain amount of heat 

 is used in evaporating the water in the wood. Air-dry wood 

 will contain from 12% to 25% water. The quality of coal 

 is another variable factor. In general, and from table below, 

 it might be said that 2| pounds of wood are equal to one pound 

 of lump coal. 



* Farrington in Hoard's Dairyman, 



