In 1797 Sir George Shuckburgh Evelyn first used a comparator by Troughton for the accurate comparison of standards. The results obtained by him are as follows: The Clerk of the House of Commons took charge of the Bird standards until they were finally adopted by Parliament under George IV. on June 17, 1824, after another exhaustive investi gation by Capt. Henry hater. The legalization went into effect January 1, 1826. The net made elaborate provision for the restoration of this standard yard from its relation to the seconds pendulum, but when- the Houses of Parliament burned down in 1834, destroying these standards. a royal commission decided against the recov cry of the standard from the pendulum, and proceeded to derive a new standard from the extant standards. This new standard was adopted June 30, 1855. In 1870 it was recom mended that mural fixed standards be established in populous towns for easy public comparison. Bronze blocks were inserted in the granite on the north side of Trafalgar Square, London. every ten feet to one hundred, and for the chain of 00 feet, and these standards were legalized in June, 1870, by act of the Connell. Frequent com mittees have recommended to Parliament the adoption of the metric system, but with no suc cess as yet. England and America will adopt the metric system at nearly the same time neither alone can get along without it.
Early in the thirteenth century it was enacted under Henry 111. that there should he uniformity in the weights and measures throughout the realm, and a little later it was determined that measures of capacity should be based upon weights. Soon afterwards weights were estab lished upon the weight of grains of wheat, as follows: 32 wheat grains = 1 penny (penny weight) ; 20 pence = 1 ounce; 12 ounces = 1 pound; S pounds = 1 gallon ; S gallons = 1 Lon don bushel; 8 bushels = 1 quarter. This known as the 'Tower pound' and was in use until the middle of the fifteenth century.
As early as the thirteenth century, the gallon appears as eight pounds of wine., and the bushel as eight gallons; also in 1452 the gallon was de fined as eight troy pounds of wheat, which in Elizabeth's time had become eight pounds avoir dupois. A statute of 1689 defines the wine gal lon as 231 cubic inches, a unit still legal in the United States. The Imperial gallon of Great Britain contains 277.274 cubic inches and is used for the measurement of all liquid and dry substances. The Imperial British bushel con tains 2218.192 cubic inches. and the Winchester bushel, the legal standard of the United States, contains 2150.42 cubic inches.
In England as well as elsewhere in Europe two pound-units have prevailed from medhrval times. a light pound for articles of high value and a heavy pound for weighing articles of low value. Many of the lighter pounds used in the Latin States are variations of the old Roman standards. others are of Saxon origin, and still others of more recent date. The Italian pounds
have varied from 300 to 350 grains. the average being about the weight of the old Roman pound of 325.8 grains. The Spanish. Portuguese, and Prussian light pounds have varied from 459 to 470 grams. The English light pound is the troy pound of 12 ounces, named from the city of Troyes, and declared a legal standard by Great Britain (1497) for weighing gold, silver, silk, and other valuable commodities. The troy pound of Elizabeth (1588) served as a standard for such articles until 1S24 (still legal in the United States), and the Imperial standard troy pound (1758) was the only legal standard in Great Britain until 1856. The present standard troy pound is defined as 5760 grains, the troy pound used in the United States.
Of the heavy or so-called commercial pounds there have likewise been a great number. Their range is practically from 15 to 24 ounces. but heavy pounds of 28 and 36 ounces are said to have been used in Milan and Valencia. The standards of France, Germany, Denmark, and Holland range mostly from 488 to 500 grams. The avoirdupois pound was recognized as a standard in England during the reign of Edward Ill., and the Elizabethan standard (1588) of 70u2 grains was derived from that of Edward. The Imperial pound avoirdupois of 7000 grains has been the English standard since 1856 and is generally copied by the United States. At the time it was legalized it was provided that in ease the standards were destroyed they were to be re covered by the fact that 1 cubic inch of water at 62' F. and a barometric pressure of 30 inches of mercury. against brass weights in air, weighs 252.458 grains. When this standard perished in 1334 with the yard, it was not recovered by this method, but from other standards.
The development of the standards of France was essentially similar to that in other countries, except that the Revolution at the close of the eighteenth century precipitated the new condi tions and resulted in the metric system (q.v.).
In the early colonial days in America the standards of the colonists were naturally those of the mother country, and in most cases copies of the home standards were brought over and intrusted to the care of special officers of the Commonwealth. In the English colonies it was usually the yard of 1588 that was employed. At the time of the Revolution the new country naturally continued with its existing English standards, and although the Constitution em powered Congress to "fix the standard of weights and measures." nothing was done for a very long time. Thomas Jefferson in 1790, at the suggestion of W'asliington, brought in to Con gress a proposition for a decimal system based upon a natural standard. Ile was not satisfied with proposed standards and urged the establish ment of the 'Leslie pendulum,' a straight bar vibrating mean seconds when suspended at one end = 38.72308 inches.