4» Of Weights and Measures . 
For the measure of weight, the Troy pound of IS 
ounces, or 5760 grains, is the integer almost always pre- 
ferred, being that which admits of a minuter subdivision, 
and whose correspondences with measures of capacity 
are more accurately defined ; though there are still some 
slight differences in this respect which it were to be wish- 
ed were removed by authority. The subdivisions of the 
Troy ounce employed by chemists are sometimes those 
of Apothecaries weight, that is, the ounce into 8 drams, 
the dram into 3 scruples, and the scruple into 20 grains, 
or more commonly, simply into drams and grains ; or 
sometimes the ounce is divided into 20 pennyweights, 
and the pennyweight into 2% grains. Often the grain is 
the only integer employed, and sets of weights are used 
of the different hundreds, tens, and units. The averdu- 
pois pound is however sometimes adopted, being the 
standard of most things bought and sold in common life. 
It is equal to 7000 grains Troy, and is divided into 16 
ounces, and the ounce legally into 16 drams, but the lat- 
ter division is never used by chemists, being liable to be 
mistaken for the Troy dram, which weighs more than 
twice as much. 
For measures of capacity, chemists employ both the 
ounce measure (or bulk occupied by the ounce, or any 
proportion of it, of distilled water at 60°) and the cubic 
inch . For larger quantities both the Wine Pint , of 
28.875 cubic inches, and the Ale Pint , of 35.25 cubic 
inches, are used. Two pints make a Quart , and four 
quarts make a Gallon . 
The correspondence between measures of weight and 
capacity is found by the weight of a cubic inch of wa- 
ter. In this however a slight difference exists, in autho- 
rities apparently equally worthy of confidence, which de- 
pends partly on the extreme difficulty of constructing 
instruments of perfect accuracy, and partly on some 
