86 FOREST CCTLTUEE AND 



during the burning process. Caution is needed to 

 prevent the expansive vapors and gases causing ex- 

 plosions during the glowing of the wood. To pro- 

 mote combustion on places where it may have been 

 suppressed, holes are forced through the covering on 

 the second or third day, particularly on the lee side. 



A bursting forth of gases of a blueish hue indicates 

 active burning, and under such circumstances the 

 access given to the air must be closed, while new per- 

 forations are made in any yet inactive portion of the 

 meiler. 



Over-great activity of fire is suppressed by water 

 applied to the covering, or by adding to the thickness 

 of the latter. Strong sinking of the cover during the 

 earlier burning proves more or less complete combus- 

 tion of the coal, and it may then become necessary to 

 refill hurriedly the holes with wood or coal, under- 

 closure of all openings, and careful restoration of the 

 cover thus temporarily removed on one spot. This 

 refilling in large meilers may be required for five days 

 in succession ; but the more carefully the mound has 

 been built, and the more watchfully the early glow- 

 ing process has been conducted, the less necessity will 

 arise for the troublesome and wasteful process of re- 

 filling. A final additional covering becomes frequent- 

 ly needful. The operation closes by the sinking of 

 the cover, or by its being partially forced downward, 

 and the ready coals are removable one day afterward. 

 Partial withdrawals of coal can be effected from the 

 lee side while the meiler is still active. 



The specific gravity of charcoal stands generally in 

 a precise proportion to the specific weight of the wood 

 employed. Dryer wood realizes a heavier, moister 



