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The Relative Importance of Slaves and Commodities in the Atlantic Trade of Seventeenth-Century Africa*

Published online by Cambridge University Press:  22 January 2009

David Eltis
Queen's University, Kingston


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Discussion Seventeenth-Century West African Trade
Copyright © Cambridge University Press 1994

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1 van den Boogaart, Ernst, ‘The trade between western Africa and the Atlantic World, 1600–90: estimates of trends in composition and value’, J. Afr. Hist., xxxIII (1902), 369–85.Google Scholar

2 Law, Robin, The Slave Coast of West Africa, 1550–1750: The Impact of the Atlantic Slave Trade on an African Society (Oxford, 1991), 175–83.Google Scholar In the long run, both theoretically and empirically, the average difference that existed between the value of trade goods as they left Europe and what Africans received for slaves and produce on the African coast was simply the cost of transporting the trade goods to the point of exchange. Presenting trade data in cowries does absorb the transportation cost factor, but cowries formed the basic currency on only a small part of the African coast (the Slave Coast) and were subject to sharp shifts in value in the short run as well as to pronounced long-term depreciation. These disadvantages are major. ‘Prime cost’ and pounds sterling are used here because there are more data available and comparisons over time and internationally are much easier. Subject to the above caveats, they are no more or less ‘African’ than a series presented in cowries.

3 Dalby Thomas to RAC, 28 April 1704, Public Record Office, London [henceforth PRO], T70/14, f.. 51.

4 Thus, if the advantage of Hawaii over Jamaica as a sugar producer had been as apparent in the seventeenth century as it was in the later nineteenth century, an African slave trade to those islands would have been even more ‘valuable’ than the one that in fact did develop to the Caribbean. Transportation costs to the Pacific would have been very high, but would the African seller of the slave have received any more income? Of course not. In fact his or her income under plausible assumptions would have been less, not more.

5 In 1973 Johannes Postma published almost verbatim a document summarizing the commodities and slaves that the Dutch West India Company (WIC) obtained from West Africa between 1675 and 1731 (Postma, , ‘West African exports and the Dutch West India Company, 1675–1731’, Economisch-en Sociaal Historische Jaarboek, xxxiv [1973], 5374Google Scholar). Slaves accounted for only 13–21 per cent of the total value of the Company's exports. But in valuing commodities the Dutch compiler obviously used the price of the commodities on their arrival in Europe, whereas for slaves - the only ‘item’ in the list not bound for Europe - the compiler used a price based on the prime cost of the merchandise in Europe that was to be exchanged for the slave. If we use van den Boogaart's convention for valuing the trade summarized in the WIC document, the picture changes dramatically. Slaves valued cif in the Americas (to match the cif in Europe for ivory, gold, etc.) constitute not 13.21 per cent of the total but rather 53.3 per cent. The basic point, however, is that neither the WIC compiler nor van den Boogaart used standard valuation practices. Consistent application of these practices to Postma's document, as shown below, shows the commodity trade to have been more important than the slave trade, but by nowhere near as much as the original breakdown suggested.

6 Estimates of the volume of the English trade at this time may be found in Eltis, David, ‘The transatlantic slave trade to the British Americas before 1714: annual estimates of volume, direction and African origins’, in Paquette, Robert and Engerman, Stanley L. (eds.), The Lesser Antilles in the Age of European Expansion (University of Florida Press, forthcoming).Google Scholar

7 ‘ Register of calculations of the Charges of Shippes and Cargoes reported by the Committee of the Court of Assistants’, PRO, T70/1222. This has been supplemented by summaries of cargoes taken from T70/50, f. 143; /61, ff. 165–6; /169, f. 135; and /175, f. 158. Three of the cargoes listed in T70/1222 and one from a companion volume, T70/1223, all intended for the Slave Coast region, have been analysed recently in Law, Slave Coast of West Africa. In addition Philip Curtin analysed 44 cargoes sent to the Gambia in the 1680s using one of the Gambia account books, T70/546. See Curtin, Philip D., Economic Change in Pre-Colonial Africa: Supplementary Evidence (Madison, 1975), 86–7 and ff.Google Scholar

8 Summaries of cargoes carried to Africa by ships of the Royal African Company are in Davies, K. G., The Royal African Company (London, 1957), especially 350–7.Google Scholar These summaries have been widely cited in the literature. The present data set is analogous to an itemised version of these with data on type of cargoes and destination added.

9 In the 10 per cent or so of cases where the nature of the return cargo is not stated, inferences are often justified. Thus there was no evidence of produce leaving the Slave Coast and very little leaving West Central Africa and the Bight of Biafra.

10 The separate slave ship data set for this period shows that 202 slave ships sailing between 1663 and 1713 obtained on average 92 per cent of their intended numbers of slaves.

11 The RAC defined the ‘Windward Coast’ as stretching between Cape Mount and Cape Three Points (T70/61, f. 3), but the phrase was also used in the sense of windward of Cape Coast Castle. The RAC instructions to the Captains used windward in the latter sense, and consistent with this, there is no doubt that the ‘windward’ cargoes were disposed of in large part on the Gold Coast before the ship reached Cape Coast Castle. This was a major source of irritation between the Agent at the Castle and the London officials. Davies, however, assumes that ‘Windward’ and ‘Gold’ Coasts did not overlap (Royal African Company, 222–8). The letters from the Company agent at Cape Coast Castle (in the T70 series) and between the Chief Agent and the outlying forts and factories on the Gold Coast (Rawlinson Mss, c 745–7, Bodleian Library, Oxford) indicate that ships acquired very few slaves with their windward cargoes.

12 Some of the cargoes were grouped together in the register, though this always seems to have been clearly indicated when it happened. Allowance for this grouping suggests that data set contains 585 cargo ‘equivalencies’.

13 For a few cargoes, values of merchandise are not supplied. These have been inferred on the basis of average values of the same period computed from cargoes of known values. There are also a few cases where the cargo was clearly intended for slaves, but the number of slaves was omitted. Again this information has been inferred from those cargoes for which the data were complete. The Schumpeter price index used to convert current to constant values is neither weighted nor broadly based. On balance, however, the advantages of using it seem to outweigh the drawbacks. The cargo lists contain several items included in the index, the major omissions being East Indian textiles, iron bars and cowries. Schumpeter presented two indexes, and I have used a simple unweighted average of the two. For the two cargoes that fall outside the 1663–97 period, one for 1698 and one for 1703, 1 ‘bridged’ the Schumpeter with the Schumpeter-Gilboy indexes (Mitchell, B. R., British Historical Statistics [Cambridge, 1988], 720Google Scholar).

14 For the start of the rum-based slave trade in the British West Indies, see E. Stede and S. Gascoigne, 26 March 1683, T70/16, f. 49. For fragmentary records of what one merchant imported into Luanda, 1684–92, see Miller, Joseph C., ‘Capitalism and slaving: the financial and commercial organization of the Angolan slave trade, according to the accounts of António Coelho Guerreiro (1684–1692)’, Int. J. Afr. Hist. Studies, xvII (1984), 43.Google Scholar The lists may even be suggestive of trade between Europeans and non-Europeans as a whole in the Atlantic area. There are broad similarities with breakdowns of goods passing through trading posts on the Upper Great Lakes of North America in the first half of the eighteenth century. See White, Richard, The Middle Ground: Indians, Empires, and Republics in the Great Lakes Region, 1650–1815 (New York, 1992), 138.Google Scholar I would like to thank Stanley L. Engerman for drawing this to my attention.

15 Calculated from Postma, , ‘West African exports’, 61.Google Scholar Philip Curtin suggested a range of 10 to 20 per cent of total imports into the Gambia for James Fort in the Gambia, but he appears to have included only building and military supplies (not personnel costs) (Economic Change in Pre-Colonial Africa: Supplementary Evidence, 87).

16 In 1709 the Lords Commissioners of Trade and Plantations, which had spent the preceding year examining trade with Africa for 1698–1707, submitted a report critical of the RAC to the House of Commons. See Donnan, Elizabeth, Documents Illustrative of the History of the Slave Trade to America (4 vols.) (Washington, 19301934), 11, 49141Google Scholar, for excerpts of this and the surrounding controversy. Donnan does not cite petitions and other material the RAC used to formulate its responses deposited in T70/175, the source of the £80,000 estimate of exports claimed by the forts (ff. 57–8). The separate (or nonRAC) traders claimed £70,000 was a more accurate figure, but the figure of £293,000 total exports from England was accepted by all (Donnan, , Documents, 11, 54–5).Google Scholar

17 As Walter Rodney pointed out long ago: ‘ Most of the long line of forts on the coastline from Axim to Accra were built originally to facilitate the trade in gold’ (‘Gold and slaves on the Gold Coast’, Transactions of the Historical Society of Ghana, x [1969], 16Google Scholar). This point was made repeatedly in the period down to 1710.

18 It should be noted that Gold Coast became a major supplier of slaves by the first decade of the eighteenth century; Eltis, David, ‘The African origins and value of the English slave trade’ (unpublished, 1993).Google Scholar In 1709, the Company reported ‘Repositorys to contain 1000 Negroes’ at Cape Coast Castle (T70/175, f. 85).

19 The King of Bonny, in the Bight of Biafra, sent a nephew to England in 1702 to press for an RAC settlement in his territory. The Company offered to establish one only if the King gave the Company preferential treatment - carefully spelled out in the letter with which the nephew returned - and the Company continued to trade from ships (RAC to the Great King of Bandie, 15 Sept. 1702, T70/51, f. 150). See also the similar efforts of the King of Kacongo in RAC to King of Cacongo, 16 Feb. 1688, T70/50, f. 57. The expenditures involved in such settlements were clearly attractive to an African élite.

20 Davies did not probe the relative importance of the slave and non-slave trades directly in Royal African Company. However, his estimates of slaves shipped from Africa, 122,500 (p. 299) at £3 each suggest total values for RAC slaves in Africa of £367,500. We can compare this with gold minted into Guineas in London at £575, 743 (p. 360), ivory sold at company sales in London, 17,113 cwt at £6 per cwt, and other produce worth £50,000 in London for a non-slave total of £728,000 in England. Half this total would approximate the value of these commodities on the African coast. Thus the slave and commodity trades would come out approximately equal. However, this computation ignores any allowance for maintenance of the castles, most of which cannot properly be assigned to the slave trade. In the early part of the period there were also sales of gold from West Africa to Asia which do not show up in the London mint figures. See Makepeace, Margaret, ‘English traders on the Guinea Coast, 1657–1668: an analysis of the East India Company archive’, History in Africa, xvi (1989), 237–9.CrossRefGoogle Scholar Makepeace calculates £133,500 from Africa to India, in 15 vessels, 1658–64 - large, by comparison with Davies' overall RAC figure.

21 For estimates of prices and total values of English slave trading at this time broken down by African region of embarkation, see Eltis, ‘The African origins and value of the English slave trade’. The RAC probably accounted for about two-thirds of total English slave trading on the Gold Coast.

22 Postma, ‘West African exports and the Dutch West India Company’. If the cost mark-up on produce between Africa and Europe was 100 per cent (van den Boogaart, 378–9), and that on trade goods sent from Europe for exchange with this produce was also 100 per cent (Eltis, , ‘Trade between Western Africa and the Atlantic world before 1870: estimates of trends in value, composition and direction’, Research in Economic History, xII [1989], 197239)Google Scholar, then goods leaving the Netherlands valued at 25 guilders (‘prime cost’) would be traded on the African coast for 50 guilders, and the produce given in exchange for these goods would be worth 100 guilders after return transportation to the Netherlands. Multiplying the value of the African produce on arrival in Amsterdam by 0.25 will thus yield an approximation of the value of the trade goods sent out to Africa.

23 Postma, Johannes Menne, The Dutch in the Atlantic Slave Trade, 1600–1815 (Cambridge, 1990), 80.CrossRefGoogle Scholar

24 For details see volume 1 of Munford, Clarence, The Black Ordeal of Slavery and Slave Trading in the French West Indies, 1625–1715 (3 vols.) (Lewiston NY, 1991).Google Scholar

25 Calculated from Patrick Manning (using Pierre Verger's data on tobacco ships for West Africa), ‘The slave trade in the Bight of Benin, 1640–1890’, in Gemery, Henry A. and Hogendorn, Jan S. (eds.), The Uncommon Market: Essays in the Economic History of the Atlantic Slave Trade (New York, 1979), 107–41)Google Scholar, and Miller, Joseph C., ‘The numbers, origins, and destinations of slaves in the eighteenth-century Angolan slave trade’, in Inikori, Joseph and Engerman, Stanley L. (eds.), The Atlantic Slave Trade: Effects on Economies, Societies and Peoples in Africa, the Americas, and Europe (Durham NC, 1992), 109.Google Scholar I have read Miller's graph to yield 110,000 for the 1660s, 130,000 for the 1670s, 125,000 for the 1680s and 105,000 for the 1690s.

26 Taken from Postma, , The Dutch in the Atlantic Slave Trade, 110, 112–13Google Scholar; and Eltis, ‘The African origins and value of the English slave trade’, table 4.

27 van Dantzig, Albert (ed.), The Dutch and the Guinea Coast, 1674–1742: A Collection of Documents from the General State Archive at the Hague (Accra, 1978).Google Scholar

28 Schwartz, Stuart, Sugar Plantations in the Formation of Brazilian Society (Cambridge, 1985), 160–93.Google Scholar For output figures see idem, ‘Colonial Brazil, c. 1580-c. 1750: Plantations and Peripheries’, in Leslie Bethell (ed.), The Cambridge History of Latin America, (Cambridge, 1985), ii, 430–1; and McCusker, John J., The Rum Trade and the Balance of Payments of the Thirteen Continental Colonies, 1650–1775 (New York, 1991), 896.Google Scholar

29 If, say, 80 per cent of Portuguese African trade comprised slaves, five, rather than seven, out of 18 (rather than twenty) slaves left Africa in Portuguese ships, the English ratio of slaves to total English African trade is set at 37 per cent, and the Dutch at 25 per cent (to allow for interlopers) then the slave trade accounts for 40 per cent of all European trade with Africa.

30 On the Brandenburgers, see Jones, Adam, Brandenburg Sources for West African History, 1680–1700 (Stuttgart, 1985).Google Scholar For the early Swedish and Danish quests for gold, see Law, , Slave Coast of West Africa, 124.Google Scholar

31 The English slave trade probably increased by two-and-one-half times in value between the 1690s and 1700–10, and the French and Portuguese slave traffics also increased sharply in this period. By comparison the gold coined into guineas by the RAC fell from £520,818 in the 25 years 1675–99 to £30,152 in the 10 years 1700–9; calculated from ‘An account of guineas coined out of Gold imported from Africa by the Royal African Company’, CO 388/25, ff. 387, 580.

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