A standard of the English foot was fixed in Old St. Paul’s Church, London, and was known as Paul’s foot, all measures being referred to the standard ‘qui insculpitur super basim columpnæ in ecclesia Sancti Pauli.’ In 1273 a deed gave the measurement of land ‘according to the iron ell [yard] of the King’s palace.’
The present standard yard is a bronze bar kept in London, the length of which agrees exactly with the yard, still extant, of Tudor times. A set of standard measures of length is fixed along the base of the northern wall of Trafalgar Square,[[14]] and another set is in the flooring of the Guildhall. Sets are also fixed to public buildings in several chief towns of the United Kingdom.
As metal rods vary in length according to temperature, comparisons with a standard measure should be made at the normal temperature of 62°. But there is an alloy of steel and nickel (42 per cent.), named Invar, which is not perceptibly affected by temperature.
A pendulum beating seconds at sea-level and at normal temperature measures 39·1393 inches at Greenwich (Act of Parliament, 1824). This length varies in different places from the variations of gravity due to the ellipticity of the earth and local causes of deviation.
3. The Hand
The popular ‘hand’ was the ‘palm’ of ancient times, four digits or finger-breadths.
Pes habet palmos iv, palmus habet digitos iv (Frontinus).
‘Foure graines of barlye make a finger; foure fingers a hande; foure handes a foote’ (Eden, 1566).
But the present Hand for horse-measurement is ‘the measure called a Handful used in measuring the height of horses, by 27 Hen. 8, Chap. 6, ordained to be 4 inches’ (Sam. Leake, 1701). This is part of an old popular duodecimal division of the foot into 3 hands of 4 inches, then of the inch into 3 barleycorns (lengthwise) each of 4 poppy-seeds, and of these again into 12 hairbreadths.
In Austria this horse-measure is the Faust or fist.