04 



PROPERTIES OF WOOD. 



contains. Maximum weights of forest-dry wood imply chiefly 

 sapwood, while minimum weights occur when the specimen 

 is chiefly heartwood. Hence the maximum forest-dry weights 

 of all species of wood vary between 100 and 130, and their 

 minimum forest-dry weights between 40 and 100. In air- 

 dry weights, the disturbing factor, water, if not excluded 

 entirely, is kept so far in the background that sapwood and 

 heartwood contain equal volumes of water. In air-dry wood, 

 therefore, the average figures given are very approximately 

 correct, the highest sp. weights of the same species varying 

 between 55 and 95, and the lowest between 35 and 80. 



The woods are grouped according to their average air-dry 

 weights, those with sp. weight of 80 and over being classed 

 as very heavy, from 70 to 80 as heavy, from 55 to 70 as 

 moderately heavy, from 40 to 55 as light, and those under 

 40 as very light. Wherever this can be done with any pre- 

 cision the sp. weight of forest-dry wood is also given. The 

 weight of a cubic meter of the wood or of a stacked cubic 

 meter (Raummeter or stere) can be calculated by multiplying 

 the figures by 10 or 7*7 respectively. [As a cubic foot of 

 water weighs 1,000 oz. = 62J Ibs., the weight of a solid cubic 

 foot of wood may be calculated from its sp. weight by 

 multiplying it by '625, and for a stacked cubic foot by '471. 

 American board-measure is in square feet of one-inch planking, 

 and is thus twelve times its volume in cubic feet. Tr.] 



TABLE OF SPECIFIC WEIGHTS OF WOOD. 



