3. The Pride and Fall of Troy
The myth of the 32 wheat-corns which formed the basis of the Tower pound = 5400 grains, passed to the Troy pound = 5760 grains, and this deliberate fiction lasted till the time of Elizabeth and perhaps later. It did little harm as regards these mint-pounds, but its application to the Averdepois pound, alleged to be an offshoot of the royal pound, either as 25 shillings, that is 300 pennyweights of 32 wheat-corns, or as 15 ounces Troy, or at a later period as 16 ounces Troy, produced a mental obliquity which is most lamentable.
The jury of merchants and goldsmiths appointed in 1574 to examine the ancient standards, and construct a new set, declared that ‘the one sorte of weight nowe in use is commonlie called the troie weight and that other sorte thereof is also commonlie called the avoir de poiz weight, and further they say that both the saide consiste compounded frome thauncient Englishe penye named a sterling rounde and unclipped which penny is limeted to waie twoo and thirtie grains of wheate in the midest of the eare and twentie of those pence make an oz. and twelf of those ounc make one pound troie.’ They go on to ‘saie that the said twoo sortes of weights doe differ in weight the one from the other three ounces troie at the pounde weight, for the pounde weight troie doth consiste onlie of xii oz. troie and the lb. weight of avoir de poiz weight dothe consiste of fiftene ounc troie.’
Thomas Hylles, in his ‘Arte of Vulgar Arithmeticke’ (1600), showed himself emancipated from the superstition of troy weight so far as to say:
‘15 ounces of Troy weight should by the statute make 1 pound of haverdepoise, but the same pound weyeth commonly but 14 ounces 1/2 Troy, 14 ounces 3/5 at the uttermost.’
(14-1/2 oz. troy = 6960 grs.; 14-3/5 oz. = 7008 grs.)
But he unfortunately went on to say that ‘of things liquid and dry 1 pound of Troy weight maketh a pinte in measure,’ not seeing that 12 oz. troy = only 13·16 oz. averdepois, while a wine-pint contained 16-2/3 ounces of water, and a corn-pint close on 16 ounces of wheat or 20 of water.
But the ignorance and superstition engendered by troy weight was just as bad in 1702 as in 1600 or even in 1500, as shown by the following utterance of an eighteenth-century scientist:
Troy weight, whereby bread, gold, silver, apothecaries’ wares etc. are weighed containing only 12 ounces in the pound, each ounce 20 pennyweight each pennyweight 24 grams. This seems to have been the most ancient weight by its name, as derived from the famous city of Troy, from whence Brutus and his people are said to have descended and to have called London Troy-Novant or New Troy.
So said J. Ralphson, F.R.S., in his ‘Mathematical Dictionary’ (London, 1702). And then he continued: