In the Troy series:

According to the subdivision for gold and silver, the ounce is divided into twenty pennyweights, and the pennyweight into twenty-four grains.

So that the pound troy contains 5760 grains, of which 7000 are requisite to make the pound avoirdupois; of course the weight of the pound troy is to that of the 7000, or as 144 to 175.

It is remarkable that this is exactly the proportion of the ancient liquid gallon of Guildhall of 224 cubic inches, to the corn gallon of 272; for 224 are to 272 as 144 to 175. [(4.)]

It is further remarkable still, that this is also the exact proportion between the specific weight of any measure of wheat, and of the same measure of water: for the statute bushel is of 64 pounds of wheat. Now as 144 to 175, so are 64 pounds to 77.7 pounds; but 77.7 pounds is known to be the weight of [(5.)] 2150.4 cubic inches of pure water, which is exactly the content of the Winchester bushel, as declared by the statute 13, 14, Will. 3. That statute determined the bushel to be a cylinder of 18½ inches diameter, and 8 inches depth. Such a cylinder, as nearly as it can be cubed, and expressed in figures, contains 2150.425 cubic inches; a result which reflects authority on the declaration of Parliament, and induces a favorable opinion of the care with which they investigated the contents of the ancient bushel, and also a belief that there might exist evidence of it at that day, unknown to the committees of 1758 and 1759.

We find, then, in a continued proportion 64 to 77.7 as 224 to 272, and as 144 to 175, that is to say, the specific weight of a measure of wheat, to that of the same measure of water, as the cubic contents of the wet gallon, to those of the dry; and as the weight of a pound troy to that of a pound avoirdupois.

This seems to have been so combined as to render it indifferent whether a thing were dealt out by weight or measure; for the dry gallon of wheat, and the liquid one of wine, were of the same weight; and the avoirdupois pound of wheat, and the troy pound of wine, were of the same measure. Water and the vinous liquors, which enter most into commerce, are so nearly of a weight, that the difference, in moderate quantities, would be neglected by both buyer and seller; some of the wines being a little heavier, and some a little lighter, than water.

Another remarkable correspondence is that between weights and measures. For 1000 ounces avoirdupois of pure water fill a cubic foot, with mathematical exactness.