[5]. The Imperial pound = 27·727 cubic inches of water, 7000 grains: the gallon 10 lb. or 277·274 c.i.
[6]. Essai sur les Systèmes Métriques (1859).
[7]. The Metretes was one-tenth more than our firkin. In the story of the Marriage at Cana (John ii.) the Greek has ‘two or three metretes.’ This term is kept in Wycliff’s version (1388) and in the modern Dutch version.
[8]. 5050 grs.—Smith’s Dict. of Antiquities. 5047 grs.—Daremberg and Scaglio’s Dict. of Antiquities.
[9]. There was a custom of rhōpi, turn of the scale, or long weight, which increased the legal commercial weight to a customary weight tending towards that of the Alexandrian talent series.
CHAPTER IV
THE INVOLUTION OF LINEAR MEASURES FROM
WEIGHTS
The Sources of the English and of the Rhineland
Foot
Commerce is the great conservator of standards. These may become altered by the ill-advised action of rulers, by municipal or parochial carelessness, even by the desire of profit on short measure, or occasionally, as seen to a slight extent in our old Bushel, by the faulty dimensions of a standard; but wholesale trade, supported, in weights at least, by the goldsmith and the apothecary, preserved the integrity of many standards during the Middle Ages and up to modern times. Commerce conveyed to the West the standards that had developed in the great Oriental Kingdoms, sometimes with the modifications due to Roman influence. Masons and architects also preserved the standards of length and, allowing for variations inevitable under the feudal system, the principal linear measures can generally be traced to their sources as surely as weights. But there are two, yea three, striking exceptions among the linear standards of the West: the English foot, and the Rhineland foot, and also the Pán of Marseilles. These are quite unconnected with any ancient measures, and there is no record of their origin. The only clue to it is found in the simple relation of each to the corresponding weights and measures of capacity, the origin of which can be satisfactorily traced. This leads to the hypothesis that these linear measures were ‘involved,’ that is produced by a method of involution the inverse of that which had evolved the measures of weight and capacity.