KILE" DRYING HANDBOOK. 
be secured with reasonable accuracy from the distribution section 
alone by assuming the original weights of all the pieces to be the 
original weight of the section, and similarly with the dry weight. 
The entire calculation will be as follows : 
Shell. 
Original weight =60 
Oven-dry weight=50 
10X100 
Moisture 
~ 50 
=20 per cent 
Core. 
Original weight =100 
Oven-dry weight= 80 
20X100 
Moisture = — ™ — 
=25 per cent 
Section. 
Original weight =160 
Oven-dry weight=130 
30X100 
Moisture 1 
130 
: 23.1 per cent 
GENERAL PRINCIPLES OF DRYING WOOD. 
The drying of wood is a very complex process, concerning many 
phases of which we are still uninformed. However, it is not essential 
that the operator understand all of the details of the movement of 
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Fig. 1. — ^iPthod of cutting 
sections from board or plank for making moisture distribution 
determinations. 
the moisture through the wood, and all of the attendant phenomena. 
Let him take it for granted, for the time being, that the moisture 
tends to distribute itself evenly through the wood, moving from the 
more moist regions to the drier ones. 
This movement of moisture within the wood is affected by three 
controllable external factors — heat, humidity, and circulation. A 
constant application of these factors in proper proportion is essen- 
tial to the successful drying of lumber to the moisture content re- 
quired for a specific use. The regulation of the heat, humidity, and 
circulation is, in fact, the main problem in the successful operation 
of kilns. 
