Linear Measures
The standard of length was the Scots Ell = 37·06 English inches. Originally three Rhineland feet at 12·353 inches, it was always described as containing 37 inches. The inch, at 1/37 of the ell, was slightly longer, by less than 2 in 1000, than the English inch. The penalty edicted in 1685 against the use of any other foot but that of 12 inches, while ‘three foot and an inch’ were a Scots ell, seems to show that a foot equal to one-third of an ell may have been used.
The rod or ‘fall’ was 6 ells; the acre was 160 square rods = 1·26 acre, and very nearly equal to the French arpent, which was equal to the Roman heredium. This is, however, a mere coincidence. The Scots acre comes, like the English acre, from North Germany. The type of the Scots acre is seen in the Jück (yoke) of Oldenburg; this field-measure is 160 square ruthen; each ruthe is 18 feet square, presumably 18 Rhineland feet = 6 Scots ells, originally; though now of a lower standard which makes the Jück = only 1·12 acre instead of the 1·26 acre of Rhineland standard.
Weights
There was an ancient weight, the Tron pound, of variable standard, about 20 Scots ounces. But its actual weight appears to have been 9622 grains, which is exactly 20 ounces of the original Arabic ounce = 481·18 grains. This was abolished by the Act of 1618, which ordered ‘that the standards be kept, two firlots by Linlithgow, the stone weight by Lanark, the ell by Edinburgh, and the pint by Stirling, as of old.’
The Lanark stone was 16 lb. of Scots Trois weight. An inscription on the standard still extant states that it was equal to 15 lb. 14 oz. English Troy, that is to the fictive long Troy pound of 7680 grains. The Scots pound, = 7609 grains, was divided into 16 ounces = 475·5 grains, divided into 16 drops.
The stone was blunderingly described (1618) as ‘the French Trois Stone containing sixteen Trois ounces.’ But it had nothing to do with French weight (in which the ounce = 472·12 grains); its standard was of the Dutch Troy (Trooisch) class, coinciding very closely with that of the Amsterdam pound = 7925 grains, the ounce = 476·5 grains.
When the 7600-grains lb. came to England as the standard of the Assize of Bread, it was known as the Scots or Dutch pound.
An Act of James I (1410), ‘That a Stone be made for weighing fifteen Trois pounds and divided into sixteen Scots pounds,’ leads to a suspicion that there was another Scots pound, of Rhineland standard; for 16 pounds or double marks of Cologne are very approximately equal to 15 long Troy pounds of English standard.
Troy oz., 480 grs. × 16/15 = 450 grs. = Tower oz.