Our next step will be to trace the process by which the as or rod became the general weight-unit, the pound (libra). The term libra is not the oldest Latin name for weight, for pondus or its cognate verb pendeo, which literally means to hang, is the true claimant for that position. Libra seems properly to mean the balance, as is seen from the legal formula (employed in Mancipatio) per aes et libram, by means of copper and the balance. From the fact that its chief use was to weigh asses of copper, the mass of an as came to be termed the weight par excellence, just as the most usual amount weighed in the Greek talanta (scales) became the talanton par excellence. This process can be illustrated by modern examples. Thus in the south of Ireland potatoes are sold by the unit of 21 lbs., which consequently is termed a weight, and instead of speaking of so many stones or hundredweights, everyone speaks of a weight of potatoes. But, as already remarked, it was only at a comparatively late epoch that the bars of copper were weighed. It would be only with the growth of greater exactitude in commercial dealings that the art of weighing, which was employed for all dealings in gold and silver, would be applied to copper. Just as the Malays and Tibetans have been gradually taught by the careful Chinese to employ weights commercially, so the Italian tribes may have been led to do so under the influence of the astute Greek traders from Magna Graecia and Sicily. The system in vogue for gold was that of our old friend the ox-unit. This is proved from the fact that not only is the oldest gold coinage of the Etruscans, the close neighbours of Latium, based upon this standard, but that also in Sicily and Southern Italy there was the small gold talent, the three-fold of the ox-unit. This three-fold of the stater was also used at Neapolis. Although the earliest Greek colonies in Sicily employed at first the Aeginetic standard for silver, we soon find them reverting to the gold or Euboic standard for that metal, whilst the early silver coinage of the Etruscans (before 350 B.C.) is also of the Euboic standard. We may with high probability assume that when the Sicilians and Italians first essayed to weigh their copper rods, they naturally employed the standard already in use for gold and silver. The highest unit of this was the small talent of 3 staters which weighed about 405 grs. The bar was divided into 12 inches, and it was found that an inch of copper rod closely approximated in weight to the small gold talent. The weight of the bar, which was the ancient unit for copper before weight had been employed, now became the standard weight-unit for that metal. It is to be observed that this ounce of 405 grs., though some 27 grs. less than the full Roman uncia of later times, is only 15 grs. lighter than the Roman ounce prior to 268 B.C., for it is an ascertained fact that the old Roman uncia did not exceed 420 grs.[429] It must be remembered that the weight of the ounce would depend on the standard foot by which the bar was measured. Now, whilst the Roman foot measures 296 millim., there was likewise in use in Campania, and probably in many parts of Southern Italy, a foot of 276 millim. The relation of bars of these lengths and of a given thickness to the Roman libra is not without interest. If we take an ordinary engineer’s table of materials we shall find that a copper rod a Roman foot long, and half a Roman inch in diameter, weighs 5040 grs. Now, as the Roman pound weighs 5184 grs. this approximation seems almost too close to be a mere coincidence. If on the other hand we take a rod of a foot of 276 millim. and with a diameter of the corresponding half-inch, we shall get a pound of 4680 grs. and an ounce of 390 grs, which is certainly not far from the weight of the small gold talent. It follows from this that we may expect pounds of different weights in Italy, according as the foot-unit varies in different districts.
In later times, besides the pound of 12 unciae, there were several commercial pounds on Italian soil, the pound of 16 ounces (from which our own avoirdupois is probably descended), that of 18 unciae, and that of 24. The last two are easy of explanation, since one is simply the double, the other one and a half times the Roman pound. But perhaps a different explanation must be sought for the 16 ounce pound. The foot was divided by Greeks and also by Italians into 16 fingers as well as into 12 thumbs. Was therefore the pound of 16 ounces simply derived from the division of the foot bar into 16 fingers, the weight of the finger being however equated to that of the Roman thumb or inch of copper?
The as, having been once subjected to weight, its hundredfold, the centumpondium or “hundred weight,” became the highest Roman weight-unit. Thus the as and the centumpondium of the Italians correspond to the mina and talent of the Greeks. But it will be observed that the Italians obtained their higher unit by the old decimal system, whereas the Greeks had borrowed the mina and its sixtyfold from Asia. The centumpondium must be regarded as a true-born Italian unit, not one borrowed from Greece or Asia, and of this there is further proof. We saw by the ancient Roman law that the cow was estimated at 100 asses, the sheep at 10 asses. No doubt from time out of mind 100 of the bars of copper, which formed the chief lower unit of barter, made one cow, just as in Annam 280 little hoes make one buffalo ([p. 167]). When copper came to be weighed, the amount of copper which formed the equivalent of the highest unit of barter, the cow, was taken as the highest weight-unit. From what I have said above it is not improbable that the Roman libra and the Sicilian litra of copper were almost equal in weight. The fact that the Greek writers always employed the Sicilian word litra (λίτρα), to translate the Latin libra, likewise indicates that in the Greek mind there was a tradition of their identity. And if the doctrine here put forward of the original nature of the as be right, nothing can be more likely than that the Italians who had crossed into Sicily and their kinsfolk who had remained behind employed rods of similar size, and that when they began to weigh the latter, the “weight” (libra or litra), derived from the standard copper rod, should be the same in each region, until certain modifications occasioned by new monetary conditions according to the needs of different communities had caused some divergency in coin weights, although as a commercial weight the litra remained unchanged. As Aristotle identified the Aeginetic obol and chalcus with the Sicilian litra and onkia, we may with some plausibility suggest that the ancient Greek copper obol or spike and the Italian as or rod were identical in dimensions and in origin.
In Greece the copper obol rapidly fell in weight, for, when once silver currency had been introduced, copper was thrust aside, and it was not till the fourth century B.C. that copper coins came into use. When the copper obol appears as a coin it is but a small piece, being in fact a mere token.
Fig. 50. As (Aes grave). (Before 2nd Punic War.)
The history of the degradation of copper was seen better in Sicily, where we found the litra still weighing 990 grs., but it rapidly sank to only 200 grs., evidently in this case also being mere money of account. For as the silver litra was about 13½ grs., unless the 200 grain copper litra was a mere token, silver would have been to copper as 17:1, which is obviously absurd. In the case of the Italian as the process is still clearer, for we have every stage of the as, from the bars which I have described through the libral as (aes grave), the sextantal as, the uncial and half-uncial, down to the small coin of the empire commonly called “a third brass.”
Fig. 51. As (half uncial standard).
