UNITS. 



XXXIX 



Besides the above measures of capacity the following volumetric units are 



used : — 



Cubic foot ^1728 cubic inches. 



Cubic yard = 27 cubic feet = 46656 cubic inches. 



Board-measure foot = i square foot X i inch thickness = 144 cubic inches. 



Perch (of masonry) — i perch (16.5 feet) length X i foot height X i-S feet 

 thickness = 24.75 cubic feet ; 25 cubic feet are commonly called a perch for con- 

 venience. 



Cord (of wood) = 8 feet length X 4 feet breadth X 4 feet height. 

 ^128 cubic feet. 



d. Measures of weight. 



The unit of weight is the avoirdupois pound. One 7000th part of this is called 

 grain, and 5760 such grains make the troy pound. The sub-multiples and mul- 

 tiples of these two pounds are exhibited in the following table : — 



a grai 



Avoirdupois. 



Dram 



Ounce = 16 drs. 



Pound = 16 ozs. 



Quarter = 28 lbs. 

 Hundred-wt. = 4 qrs. 



Long ton =20 cwt. 



Short ton = 



^h lb. 



I " 



28 " 

 112 « 



2240 " 

 2000 " 



Troy. 



Grain 



Pennyweight 

 Ounce 

 Pound 



20 grs. 

 24 dwt. 

 12 ozs. 



= 5^^ lb. 



