The Ounce in Eighteenth-Century West African Trade

Abstract

The Ounce as a unit in the West African trade was originally applied to the goods which could be exchanged on the Gold Coast for one ounce of gold; it was generally reckoned that such goods would cost about 40s. in Europe, or half the European value of the gold. Calculations based on actual transactions show that the prime cost of an Ounce of goods was sometimes lower than this, when a favourable assortment of goods had been chosen. In the 1760's and 1770's gold was no longer being exported from the Gold Coast, but was demanded as part of the price of slaves; an ounce of gold was then valued at two Ounces of trade goods. The price of gold had risen, partly owing to a local stoppage of trade, and perhaps also because of a permanent change in the direction of Ashanti gold exports.At Whydah, the Ounce was not in use in the first half of the eighteenth century; values of goods, including cowries, the local currency, were expressed in terms of the quantity equivalent to one slave. By 1772 the Ounce had come into use at a value similar to that on the Gold Coast. The French selling cheap brandy, and the Portuguese selling cheap Brazilian tobacco, were able to operate at very low costs per Ounce.The ‘slave-price’ rigsdaler of Christiansborg, with regular exchange rates both with gold and with cowries, forms a link between the Gold and Slave Coast systems.A table of slave prices at various dates during the seventeenth and eighteenth centuries is given in terms of Ounces and other units.