Ax J: HiiN UiA 1 



EXPLAISTATION OF SOME TERMS USED WITH REFERENCE TO 



CONVERTED TIMBER, ETC. 



It may be useful to give here the following dejfinitions of terms used in the 

 English timber trades. (See also p. 76 swpra.) 



A balk is a log rougHy squared. 



A plank is 11 in. broad, from 2 to 6 in. thick, and generally from 8 to 21 ft. 

 in length. 



A deal is 9 in. broad and not more than 4 in. thick. 



A batten is not more than 7 in. broad. 



A square is 100 ft. superficial. 



A hundred of deals is 120. 



A load is 50 cubic feet of squared timber, or 40 cubic feet of unhewn, or 

 600 superficial feet of inch planking. 



The simplest formula for measuring timber is : 



o=l(^±|±s^)' 



where C= the cubic contents in cubic feet ; L= the length of the log in feet ; 

 G— one-fourth of the girth of the tree midway in its length, in feet ; gr= one- 

 fourth of the girth at one end, in feet ; g'= one-fourth of the girth at the 

 other end, in feet ; a deduction for bark being made from each quarter-girth. 



The ratio of calliper measurement of the diameter of a tree to "siding" 

 is as 99 : 70, or, roughly, as 10 : 7 — e.gr., 10 in. diam. gives 7 in. in the side ; 

 15 in, give lOJ; 20 gives 14; etc. 



Water weighs 62*321 lbs. per cubic foot; therefore wood, of which W — i.e., 

 the weight per cubic foot — ^is 62, has the specific gravity which is stated as 1, 

 or sometimes (dropping decimal points) as 1,000. As we use W to express 

 the weight in lbs. per cubic foot, and S.G. to represent the density or specific 

 gravity — Le., the weight as compared with water — ^we find the S.G. by 

 dividing 62 32 into W. Woods have specific gravities between '26 and 1*3^ 

 or 260 and 1,300 — i.e., W ranges from 13 to 85 (see p. 35). 



In comparison with the Metric system it is convenient to reckon a decimetre 

 as =4 in., a metre as =3^ ft., a kilogram as==2| lbs., and a ton as =1,016 kilos. 



A cubic centimetre of water, at the standard temperature and pressure, 



303 



