| Col. Lambton Standard (Indian Survey) | 36·000000 | inches. |
| Bird’s Standard (1760) | 36·000659 | “ |
| Sir Geo. Schuckburgh’s Standard | 36·000642 | “ |
| Ramsden’s Bar. Ordnance Survey | 36·003147 | “ |
| Gen. Roy’s Scale | 36·001537 | “ |
| Royal Society Standard | 36·002007 | “ |
The commission reported in favor of adopting Bird’s standard of 1760, as it differed so slightly from Sir George Schuckburgh’s standard (which had been used in deducing the value of the French mètre) that those values could be assumed as correct. They also established the length of the seconds pendulum at level of sea in London and in vacuo as 39·13929 inches. The seconds pendulum had been previously fixed by Wollaston and Playfair in 1814 as 39·13047 inches.
On this report, an Act of Parliament in 1823 declared the only standard measure of length for the United Kingdom to be the yard as given by the distance at 32° F. between two points in gold studs on the brass bar, made by Bird, and marked “Standard of 1760,” and in the keeping of the Clerk of the House of Commons; also it referred this standard yard to the natural standard of a pendulum vibrating seconds of mean solar time at the level of the sea, in vacuo at London and temperature of 32° F., as in the proportion of 36 to 39·13929; so that a pendulum 36 inches long ought to make 90088·42 vibrations in 24 hours.
The Royal Society had a copy of the legal standard made by Bailey in 1834; and in the same year the Parliamentary standard was destroyed by fire at the burning of the Houses of Parliament, leaving the kingdom again without a legal standard.
All attempts made by a commission consisting of Airy, Bailey, Herschel, Lubbock, and Sheepshanks, to restore the standard by means of the seconds pendulum failed in exactness, on account of the many conditions of a vibrating pendulum, and recourse was had to the Royal Society standard, which had been carefully compared by Captain Kater in 1818, and from this in 1838 Bailey and Sheepshanks made six bronze bars, one inch square, and 38 inches long, which in 1855 were legalized by Act of Parliament, and the English standard of length defined as follows:
“That the straight line on distance between the centres of the transverse lines in the two gold plugs on the bronze bar deposited in the Exchequer shall be the genuine standard yard at the temperature of 62° Fahrenheit; and if lost, it shall be replaced by means of its copies.”
The French metrical system was made legal permissively in 1864, at the length established by Captain Kater, referred to in Act of Parliament of 1823, of 1 mètre equal to 39·37079 inches, or 3·28089916 feet.
These are the standards now in use in the United Kingdom.
UNITED STATES.
By the Constitution of the United States Congress is charged with fixing the standard of measures (Art. 1, sec. 8); but as no enactment has been made by Congress, the standard yard in England, which was legal previous to 1776 in the Colonies, is the standard yard of the United States, and does not differ with the English standard yard.