Arm rings are made from solid brass rod about ⁷⁄₁₆ in. thick and are usually 2½ in. to 3½ in. in diameter—they are also made in large quantities from brass tubes of ½ in. to ⅝ in. diameter, more frequently from ⁹⁄₁₆ in., the rings being from 2½ in. to 3½ in. in diameter, and weighing from 2½ to 4 oz. each[70]. * * * * * Slaves and ivory tusks form the chief units in the same region. The slave usually is worth a tusk. In other parts pieces of precious wood of a red colour, each piece being a foot long, were employed as currency[71]. When we come to regions where the ox can live we at once find that animal occupying a foremost place. Thus when the Cape of Good Hope was first colonized, the Hottentots employed cattle and bars of iron of a given size as currency[72], and at the present moment the cow is the regular unit among the Zulus, ten cows being the ordinary price paid for a wife, although as in Homeric Greece fancy prices are paid by the chiefs for ladies of uncommon attractions. But our chief interest must centre in the peoples north of the Equator, who from time immemorial have been in contact with the ancient civilization of the Mediterranean. Thus among the Madis of Central Africa, a pure negro tribe, cattle form the chief wealth; a rich man may have as many as 200 head, a very poor one only 3 or 4. The average number possessed by one man is from 30 to 40. They keep the milk in gourds. “A regular system of exchange is carried on in arrows, beads, bead necklaces, teeth necklaces, brass rings for the neck and arms, and bundles of small pieces of iron in flat, round, or oval discs. All these different articles are given in exchange for cattle, corn, salt, arrows, etc. The nearest approach to money is seen in the flat, round pieces of iron which are of different sizes, from three-quarters to two feet in diameter and half an inch thick. They are much employed in exchange. This is the form in which they are kept and used as money, but they are intended to be divided into two, heated and made into hoes. They are also fashioned into other implements, such as knives, arrow-heads, etc. and into little bells hung round the waist for ornament or round wandering cows’ necks. Ready-made hoes are not often used in barter. Iron as above-mentioned is preferred and is taken to the blacksmith to be fashioned according to the owner’s requirements. Any tools may be obtained ready made from a smith, and can be used in barter when new. “Compensation for killing a woman or any serious crime must be paid for in cattle. No cowries are used as coins in this district, no measure of weight, quantity or length is used. The payment for a wife must be made in cows of a year old, or in bulls of two or three years[73].”