cattle-trading came in which could tend to level the value on both sides of an arm of the sea. In the earlier half of this century cattle were extraordinarily cheap in Ireland in proportion to the prices which they fetched in England, but yet the difficulty and expense entailed in sending them across in sailing ships effectually prevented the export. When the first steamers began to convey cattle from Ireland to England the profits were enormous, although the freight of a single cow cost, I believe, several pounds. Steam-power has done much to equalize prices, but still there is a considerable difference in the value of cattle on both sides of the Irish Sea. But where no impassable barrier of sea or forest intervened, we may fairly assume the ox carried much the same value from Northern India to the Atlantic Ocean.
We have already proved in the case of most of the peoples with which we have to deal that the ox was the unit of value. We have likewise found that these primitive peoples, whilst employing a cow or ox of a certain age as their standard of value, had adjusted accurately to this unit their other possessions: for instance, the heifer of the second year bore a distinct value relatively to the cow of the third year, so likewise the calf of the first year and the milk of a cow for a certain period. These thus acted as submultiples of the standard unit, and as they were the same in kind and only differed in degree, the various sub-units of the cow remained in constant proportion to the chief unit and to one another. On the other hand, when there was a distinction in kind between animals, as between oxen and sheep, the relative value would probably differ according to the scarcity or abundance of either kind of animal, which difference would probably arise from a difference in the nature of the pastures and climate. Thus we have found in some places ten sheep regarded as the equivalent of an ox, in others again eight. The same holds good of goats. In the case of these smaller animals we have seen the same fixed scale of values according to age, and the same method of rating the value of the milk of an ewe or the goat as we find in the case of the cow. Amongst people who possessed horses, camels and
