3. Corn Measure
It has been seen that Henry III’s statute defined the gallon as containing 8 lb. of wine, and Edward I’s as containing 8 lb. of wheat. It is probable that the Magna Charta principle of ‘one weight, one measure’ prevented the mention of two different gallons, as it prevented the mention of two different pounds. But we know that there were two gallons. In England as in ancient Greece the unit of corn-measure was the fluid measure of the Talent increased in water-wheat ratio; so our cubic foot, taken as a wine-bushel of 8 wine-gallons, and increased one-fourth, gave the corn-bushel of 8 corn-gallons.
| 1728/8 c.i. | = | 216 c.i., the original wine-gallon, |
| 1728 c.i. × 1·25 | = | 2160 c.i., the corn-bushel, |
of which 1/8 = 270 c.i. was the corn-gallon.
It has been seen that the wine-gallon increased to 231 c.i., but the corn-standard remained for centuries (excepting a vagary temp. Henry VII and VIII) at very nearly its original value. It must be remembered how difficult it must have been to cast accurately a shallow brass pan 18-1/2 inches in diameter and only 8 inches deep; and this is probably the cause of the slight difference between the two standards of corn-measure, the London bushel and the Winchester bushel. These were simply variants, inevitable in making standard measures of the calculated capacity of the bushel = 2160 cubic inches = 1-1/4 cubic feet.
The London bushel = 2150·42 c.i.; the gallon = 268·8 c.i.
The Winchester bushel = 2178 c.i.; the gallon = 272-1/4 c.i.
The latter standard was so called, it is said, because its standard had been kept at Winchester since the time of King Edgar; it was, by 22 Chas. II (1670) and 10 Geo. III (1769), the standard measure for corn and other dry goods.
But by 13 Wm. III (1702) and by 5 Anne (1707) the London bushel was the standard, and this is the present corn-bushel of the United States. It is, however, commonly called, but inaccurately, a Winchester bushel.