24 BULLETIN 753, U. S. DEPARTMENT OF AGRICULTURE. 
28 days, according to size of kiln. The contents vary from 4 to 60 
cords. 
Beginning at the leeward side the kiln is gradually uncovered. 
The crust of earth, cut into fragments, is thrown on again. The 
earth trickling down quenches the fire. After another 12 to 24 
hours, preferably at night, the coal is taken out in patches or pockets, 
slowly and carefully, so as to prevent the flames from breaking out. 
Water must be at hand to quench incipient fires. 
HOW TO USE WOOD FUEL. 
Coal has been so generally used lately and furnaces and stoves have 
become so adapted to its use that it seems impractical to many to 
burn wood without going to great expense. Such is not usually the 
case, as simple adjustments will allow wood to be used with coal- 
burning equipment. The size of the firebox, of course, gives the 
greatest difficulty, since in many cases it may make it necessary to 
cut the wood into very small blocks. This trouble, however, is not in- 
surmountable and is not so expensive as it might seem. The matter 
of adjusting the drafts and arranging the grates is simple. 
Following are a number of practical directions which are largely 
the result of experience in changing from coal to wood fuel. 
BURNING WOOD IN STOVES. 
A coal-burning stove can be converted into a wood-burning stove 
by removing the fire brick and substituting lighter bricks at a cost 
of about $1.25. Most country cook stoves can burn wood with little 
trouble. Ifa stove grate is too coarse for Wood, a sheet-iron cover over 
a good part of the surface will make it suitable, or a few fire bricks 
can be used. Wood grates made in two pieces are sold which can be 
inserted through the fire door and placed on top of the regular 
grate. | 
BURNING WOOD IN FURNACES.! 
Furnaces are built especially for burning wood in 3 or 4 foot 
lengths. Short lengths, of course, can readily be burned in an ordi- 
nary coal furnace or in a box stove, though this is rather wasteful of 
fuel. Many furnace manufacturers, however, make a special wood 
grate for use in their furnaces. One advantage in burning wood is 
that on moderately cool days the furnace can be run at a lower ebb 
than when coal is used, consuming only enough fuel to remove the 
chill. When wood is used in a round pot furnace care should be 
taken to have each piece lie flat. 
1Adapted from a bulletin by HE. H. Lockwood, published by P. B. Noyes, director of 
conservation, U. S. Fuel Administration, Washington, D. C. 
