This article provides a synthesis of the various studies which attempt to quantify the trans-Atlantic slave trade. Since the publication of Philip D. Curtin's pioneering estimates in 1969 (The Atlantic Slave Trade: A Census), there have been numerous revisions of different sectors of the trade, and some scholars – notably J. E. Inikori and James Rawley – have argued that Curtin's global estimate for imports into the Americas is too low. When the revisions are examined carefully, however, it is apparent that Curtin's initial tabulation was remarkably accurate. The volume of exports from Africa across the Atlantic is here calculated at 11,698,000 slaves, while imports into the Americas and most other parts of the Atlantic basin are estimated to have been 9·8–9·9 million slaves – well within range of Curtin's original Census. Many of the revisions are based on shipping data by national carrier, rather than on series derived from estimated imports into different colonies in the Americas. Hence it is possible to substitute new data for much of the eighteenth and nineteenth centuries for many of the import-derived series used by Curtin. The results of these substitutions shift the distribution of slave exports over time but do not affect estimates of the relative scale of the trade by more than 2–3 per cent – hardly significant considering the quality of the data. Inikori and Rawley have failed to distinguish clearly between imports by colony and exports by national carrier; hence their global estimates have resulted in double counting. Further revisions are likely, nonetheless, but until the completion of detailed research comparable to the studies of David Eltis, Roger Anstey, Johannes Postma, and a dozen other scholars it is not possible to estimate the extent of future modifications. In the meantime, the current state of research on the volume of the Atlantic slave trade is summarized in a series of tables which analyse the export trade by time period, national carrier, and coastal origin. It is expected that the present synthesis will challenge historians to examine the impact of the slave trade on different parts of Africa, both to test the regional breakdown of slave exports and to assess the demographic, political, economic and social repercussions on Africa.
2 Curtin, Philip D., The Atlantic Slave Trade: A Census (Madison, Wisconsin, 1969), 268.
3 Curtin, , Census, xviii.
4 Inikori, J. E., ‘Introduction’, in Forced Migration: The Impact of the Export Slave Trade on African Societies (London, 1981), 20. Also see Inikori, , ‘Measuring the Atlantic slave trade: an assessment of Curtin and Anstey’, Journal of African History, XVII, ii (1976), 197–223; Inikori, , ‘Measuring the Atlantic slave trade: a rejoinder’, Journal of African History, XVII, iv (1976), 607–27; and Inikori, , ‘The origin of the Diaspora: the slave trade from Africa’, Tarikh, v, iv (1978), 8.
5 Inikori, , ‘Introduction’, 19.
6 Fage, J. D., ‘Slavery and the slave trade in the context of West African history’, Journal of African History, x, iii (1969), 393–407.
7 See, for example, Inikori, Forced Migration, which contains an excellent sample of articles and sections of books relating to the debate; Anstey, Roger, The Atlantic Slave Trade and British Abolition, 1760–1810 (London, 1975), 58–88; and my own study: Transformations in Slavery: A History of Slavery in Africa (Cambridge, forthcoming).
8 Fage, J. D., A History of Africa (London, 1978), 244–88.
9 Manning, Patrick, ‘The enslavement of Africans: a demographic model’, Canadian Journal of African Studies, XV, iii (1981), 499–526; and Slavery, Colonialism and Economic Growth in Dahomey, 1640–1960 (Cambridge, 1982). It should be noted that Manning is working on a book which will examine the demographic impact of the slave trade on Africa; see his preliminary paper, ‘The political economy of African slavery’, presented at the Johns Hopkins University, 1 12 1981.
10 Thornton, John, ‘The slave trade in eighteenth century Angola: effects on demographic structures’, Canadian Journal of African Studies, xiv, iii (1980), 417–27.
11 Inikori, , ‘Introduction’, 20–59.
12 For example, Anstey, (Atlantic Slave Trade, 79–88) argues that there was no net population loss in the interior of the Bight of Biafra. Northrup, David. Trade without Rulers: Pre-Colonial Economic Development in South-Eastern Nigeria (Oxford, 1978), 81–2, argues that the region only sustained the loss of population because of higher natural growth rates than Anstey allows.
13 Stein, Robert, ‘Measuring the French slave trade, 1713–1792/3’, Journal of African History, xix, iv (1978), 515–21. Also see Stein, , The French Slave Trade in the Eighteenth Century: An Old Regime Business (Madison, 1979). Stein notes that‘It must be recognized that the estimates advanced by Curtin for French slave exports were too low… due to the quality of the available published data’. (‘Measuring’, 520.)
14 Anstey, Roger, ‘The volume and profitability of the British slave trade, 1761–;1807’, in Engerman, Stanley and Genovese, Eugene, eds., Race and Slavery in the Western Hemisphere: Quantitative Studies (Princeton, 1975), 12. Anstey's estimate is ‘based on material not known to Curtin's authorities and therefore supersedes his results’.
15 Vilar, Enriqueta Vila, ‘The large-scale introduction of Africans into Veracruz and Cartagena’, in Rubin, Vera and Tuden, Arthur, eds., Comparative Perspectives on Slavery in New World Plantation Societies (New York, 1977), 267–80; and Hispanoamerica y el comercio de esclavos: Los Asientos Portugueses (Seville, 1977).
16 Eltis, David, ‘The export of slaves from Africa, 1821?–1843’, Journal of Economic History, xxxvii (1977), 410–15; and ‘The direction and fluctuation of the Transatlantic slave trade, 1821–1843: a revision of the 1845 Parliamentary Paper’, in Gemery, Henry and Hogendorn, Jan, eds., The Uncommon Market: Essays in the Economic History of the Atlantic Slave Trade (New York, 1979), 273–301; see especially page 291. It should be noted that D. R. Murray was one of the first to question the accuracy of Curtin's estimates (‘Statistics of the slave trade to Cuba, 1790–1867’, Journal of Latin American Studies, iii, ii, 1971, 131–49). Murray demonstrated that imports into Cuba were greater than Curtin allowed. In my calculations, Murray's comments are not relevant for two reasons. Firstly, I base my estimates on the volume of slaves carried by the ships of different countries and not by import area for 1790–1810. Secondly, I rely on Eltis's research for the period after 1820, which supersedes Murray's work. It should be noted also that the totals in Murray's article have been corrected in his book: Odious Commerce: Britain, Spain and the Abolition of the Cuban Slave Trade (Cambridge, 1980), 18, 80, 111, 112, 244.
17 Rout, Leslie B. Jr, The African Experience in Spanish America: 1502 to the Present Day (Cambridge, 1973), 65.
18 Curtin, , Census, 3–13.
19 Inikori, , ‘Assessment of Curtin and Anstey’, 197–223; ‘Rejoinder’, 607–27: ‘Introduction,’ 19–21, 277–8 fn; Curtin, Philip D., ‘Measuring the Atlantic slave trade once again’, Journal of African History, xvii, iv, (1976), 595–605; Anstey, Roger, ‘The British slave trade 1751–1807: a comment’, Journal of African History, xvii, iv (1976), 606–7; and Drescher, Seymour, Econocide: British Slavery in the Era of Abolition (Pittsburgh, 1977), 205–13.
20 Inikori, , ‘Introduction’, 20–1.
21 Rawley, James A., The Transatlantic Slave Trade: A History (New York, 1981), 428, for a summary of Rawley's calculations. In an earlier article, Rawley demonstrated that the London share of the eighteenth-century British trade was much greater than previously known and indicated that upward revision in the British trade was necessary to allow for his reassessment. He did not present alternative figures at the time, however. See ‘The port of London and the eighteenth century slave trade: historians, sources and a reappraisal’, African Economic History, ix (1980), 85–100. The revision suggested is an additional 75,000 slaves (Slave Trade, 428).
22 Rawley refers to table 7.1 (Slave Trade, 165) for British exports, 1690–1807, and adds 75,000 slaves to compensate for what he claims is an allowance for the previously underestimated London trade. These calculations produce an estimate for the volume of British slave exports from Africa, not the number of slaves imported into the British Caribbean. Furthermore, Rawley accepts Curtin's calculations for imports into the British Caribbean (pp. 164–7 and table 7.3), although table 7.3 does not record all the slaves tabulated by Curtin for the British Caribbean (see Census, 140). Rawley provides no explanation for the discrepancy. Rawley also makes the mistake of adding an estimate for slaves carried on British ships after 1807, basing this revision on the estimated 80,000 slaves calculated by Eltis, David (‘The British contribution to the nineteenth-century Transatlantic slave trade’, Economic History Review, xxxii, ii, 1979, 226). Rawley again mixes exports by national carrier with imports by receiving area. British-transported slaves and slaves imported into British territory are simply not the same. For imports into Brazil before 1600, Rawley has counted all Portuguese slave imports as Brazilian imports, which produces an error for Brazil of 224,900 slaves, since these imports are also included in his totals for the Old World and Spanish America (see table 2.1, p. 25, which is derived from Curtin, Census, 116, for the period 1451–1600). There is another error in the nineteenth-century calculation: Rawley refers to Eltis, (‘Transatlantic slave trade, 1821–1843’, 273–301) in modifying Curtin's figure, but Eltis raises Curtin's total for 1821–43 by 192,100 (p. 289), not 300,000 as Rawley has it. The combined error is 332,800 for Brazil and 778,000 for imports into the British Caribbean. It also should be noted that Rawley refers to Table 14.1 as a source for his estimate for imports into British North America, but since there is no such table it is not possible to examine his calculations.
23 Rawley relies on Duncan, T. Bentley, Atlantic Islands; Madeira, the Azores, and the Cape Verdes in Seventeenth Century Commerce and Navigation (Chicago, 1972), 210.
24 The Royal African Company recorded losses in transit of 23.5 per cent between 1680 and 1688 (Davies, K. G., The Royal African Company [New York, 1970], 292); Dutch exports suffered to the extent of 17·9 per cent losses in transit between 1637 and 1645 (sample of 27,477 slaves) (van den Boogaart, Ernst and Emmer, Pieter C., ‘The Dutch participation in the Atlantic slave trade, 1596–1650’, in Gemery, and Hogendorn, , Uncommon Market, 367). Also see Curtin, , Census, 276–7.
25 In her initial tabulation, Vila Vilar estimated that 220,800 slaves were imported through Cartagena and Vera Cruz alone between 1595 and 1640 (‘Veracruz and Cartagena’, 275), but she later revised these figures as follows: Cartagena, 135,000; Vera Cruz, 69,560; Rio de la Plata, 44,000; and the Caribbean islands, 19,664 (Comercio de esclavos, 206–9). Her total is 268,664, but I have added these figures as 268,200, rounding off to the nearest hundred. Vila Vilar's figures replace the earlier estimates of Beltrán, Gonzalo Aguirre, La población negra de México, 1519–1810 (Mexico, 1946), 220, whose figure of 132,600 was used by Curtin in calculating the imports into Spanish America in this period (Census, 23). It should be noted, however, that my figures for the whole period from 1575 to 1650 are calculated as follows: I used Curtin's average for each quarter century to account for the years not covered by Vila Vilar. Inikori does not refer to Vila Vilar's work.
For the period before 1595, Colin A. Palmer has challenged Curtin's estimate for Spanish American imports, raising Curtin's figure (51,300) (Census, 25) to 73,000; see Slaves of the White God: Blacks in Mexico, 1570–1650 (Cambridge, Mass., 1976), 26–8, but because my recalculation of the totals based on Vila Vilar, Fogel and Engerman, and Curtin is higher than a simple addition of the revisions to Curtin's original figure, I have not adjusted for Palmer's suggestion. It should be noted, moreover, that Palmer's estimate is not based on as strong evidence as the other two revisions. He relies on two population estimates for the number of slaves in Spanish America, as well as scattered information on various contracts to deliver slaves. The first population estimate, for 1553, indicates a slave population of 20,000, which seems too high. The second, for 1570, indicates a similar level, which seems more likely (p. 28).
26 Fogel, Robert and Engerman, Stanley, Time on the Cross: Evidence and Methods (Boston, 1974), 30. Fogel and Engerman calculated the following time pattern: 1620–50, 1432 slaves; 1650–70, 1946 slaves; 1670–80, 1443 slaves; 1680–1700, 15,659 slaves; total, 20,480 slaves. (Personal communication, S. Engerman.) I have rounded off the figures to the nearest hundred and divided the estimates into quarter centuries.
27 Curtin, , Census, 21–5. Curtin estimated that 516,100 slaves were imported into Spanish America between 1641 and 1773, for an average of 3,880 slaves per year.
28 Preciado, Jorge Palacios, La Trata de Negros por Cartagena de Indias (Tunja, 1973).
29 Preciado, , Trata de Negros, 29, 39 fn.
30 Curtin, , Census, 25.
31 Preciado, , Trata de Negros, 30–1.
32 Ibid., 31.
33 Ibid., 32.
34 Ibid., 99.
35 Certainly the imports into Buenos Aires, which was only a minor centre of the trade in this period, were small; see Chace, Russell, ‘The African impact on colonial Argentina (Ph.D. thesis, unpublished, University of California, Santa Barbara, 1969), 36–41. Chace notes that the volume of imports probably was on the order of 500–600 slaves per year in the 1640s, but in the second half of the century, when the Spanish colonies suffered an economic recession, trade was unstable at best.
36 Postma, Johannes, ‘The origin of African slaves: the Dutch activities on the Guinea Coast, 1675–1795‘, in Engerman, and Genovese, , Race and Slavery, 49; and Postma, ‘The Dutch slave trade: a quantitative assessment’, Revue française d'histoire d'outre-mer, lxii (1975), 237. Postma bases his study on the records of the Dutch West India Company.
37 Stein, , ‘French slave trade’, 519; and Stein, , French Slave Trade, 11, 207. Stein bases his study on the records of the Amirauté which kept detailed accounts of ships and cargoes.
38 Drescher, , Econocide, 28; Anstey, , ‘British slave trade’, 13; and Inikori, , ‘Assessment of Curtin and Anstey’, 213–4. Drescher and Inikori used Customs series 3 and 17 in the Public Record Office for 1777–1807, while Anstey used clearance lists for British ships for 1761–1807.
39 Klein, Herbert, The Middle Passage: Comparative Studies in the Atlantic Trade (Princeton, 1978), 27. Klein used shipping records from Rio de Janeiro and Angola for the Portuguese trade.
40 Green-Pedersen, Svend Erik, ‘The history of the Danish Negro slave trade, 1733–1807’, Revue française d'histoire d'outre-mer, lxii (1975), 201. Green-Pedersen relies primarily on the records of the Great Negro Trade Commission of Denmark.
41 For Anstey's synthesis of the continental trade, see ‘The slave trade of the continental powers, 1760–1810’, The Economic History Review, xxx, ii, (1977), 261. In his reconstruction, Anstey relies on the work of Herbert Klein, Postma, Green-Pedersen and Curtin. For the North American trade, see Anstey, , ‘The volume of the North American slave-carrying trade from Africa, 1761–1810’, Revue française d'shistoire d'outre-mer, lxii (1975), 65. Anstey uses widely scattered data in his synthesis of the North American trade, especially the material in Donnan, Elizabeth, ed., Documents Relating to the Slave Trade (Washington, 1930–1935), which includes some archival material (e.g. Charleston Customs records, 1803–7). Fogel and Engerman have provided some verification of Anstey's revision: they calculate that Curtin's estimate for total imports into the United States was 148,000 too low for the period 1760–1810 (Time on the Cross: Evidence and Methods, 30–1).
42 Stein, , French Slave Trade, 11, 207. Ships carried an average of 306 slaves; hence the 33 documented ships may have had as many as 10,000 slaves on board. Stein does not state when these ships sailed, and some, if not most, may have traded in 1711 or 1712. For my purposes, however, I am assuming that these 33 ships contributed to the portion of the total French trade assigned to 1701–10.
43 Scheuss de Studer, Elena F., La trata de negros en el Rio de la Plata durante el siglo XVIII (Buenos Aires, 1958), 126. For a fuller discussion of the Argentine trade, see Chace, , ‘African Impact on Argentina’, 47–51.
44 Preciado, , Trata de Negros, 165. It should be noted that Preciado's data on imports into Buenos Aires differs from Scheuss de Studer's figure. Preciado accounts for 3,057 slaves.
45 Stein would allow for one or two ships per year (personal communication). This estimate for the unrecorded vessels is partially confirmed by Clark, John C. (La Rochelle and the Atlantic Economy during the Eighteenth Century [Baltimore, 1981], 29), who records eight ships leaving for Africa between 1710 and 1719 and eleven ships between 1720 and 1729, although the size of the ships and the number of slaves purchased are not known. Stein appears to have included a few of these ships – for the years 1728 and 1729 – but not the others. I wish to thank Professor Stein for discussing this problem with me. I have not attempted to compare Stein's material with the data on the French trade collected by Mettas, Jean (Répertoire des expeditions negrières françaises au XVIIIe siècle, ed. Daget, Serge, Nantes, 1978). A second volume of material collected by Mettas is forthcoming.
46 Preciado, , Trata de Negros, 312.
47 Op. cit. 338.
48 Op. cit. 32–3, 40 fn.
49 Chace, , ‘African impact’, 53–64.Palmer, Colin A., Human Cargoes: The British Slave Trade to Spanish America (Chicago, 1981), 110–11, shows Baritish imports into Spanish America, 1715–39, as 74,760, with illicit trade another one-third to one-half – 3,000–15,000 higher that Curtin's figures for these years. But as Curtin used an annual average (3,880) for the period 1641–1773, his estimate is not altered significantly, if at all.
50 Anstey, , ‘British slave trade’, 3–31; see especially p. 13.
51 Inikori, , ‘Assessment of Curtin and Anstey’, 214; and Drescher, , Econocide, 28.
52 Anstey, , ‘Comment’, 605–6.
53 Inikori, , ‘Assessment of Curtin and Anstey’, 214 for estimates of 2,365,014, making allowance for non-slave carrying vessels, and 2,476,959, assuming unrecorded ships more than made up for non-slave carriers. Inikori, , ‘Rejoinder’, 624, presents different estimates: 2,307,986, taking no account of unrecorded trade, and 2,416,910, taking into account unrecorded trade. Inikori does not indicate how he arrived at these conflicting figures.
54 Drescher, , Econocide, 28. Drescher's calculation is 10·4 per cent higher than Curtin's original estimate, while Inikori's figure is 48·8 per cent higher.
55 Anstey's revision for 1751–1807 is 1,913,380 slaves (‘Comment’, 607), while Curtin's figure for 1701–50 is 863,900 (Census, 142). Drescher's estimate of 245,000 slaves for 1801–1807 is in Econocide, 28.
56 Inikori, , ‘Rejoinder’, 624.
57 Curtin, , Census, 210–20.
58 Postma, , ‘Origin of African slaves’, 49.
59 Curtin, , Census, 212.
60 Postma, , ‘Origin of African slaves’, 49.
61 Green-Pedersen, , ‘Danish Negro slave trade’, 201; Anstey, , ‘Continental powers’, 267; and Anstey, , ‘North American slave-carrying trade’, 65.
62 Eltis, , ‘Transatlantic slave trade, 1821–1843’, 273–301; and Eltis, , ‘The direction and fluctuation of the transatlantic trade, 1844–1867’, unpublished paper presented at the African Studies Association annual meeting, Bloomington, Indiana, 1981. It should be noted that Eltis's revision of 1844–67 supersedes the calculations of Murray, David R., Odious Commerce: Britain, Spain and the Abolition of the, Cuban Slave Trade (Cambridge, 1980). I have not seen Serge-Daget's thesis on the nineteenth century French trade, but a preliminary discussion is provided in ‘British repression of the illegal French slave trade: some considerations’, in Gemery, and Hogendorn, , Uncommon Market, 419–42. Daget accounts for approximately 118,000 slaves exported on French ships before 1845. Eltis has allowed for the illegal French trade, although his calculations may be low; see ‘Transatlantic slave trade, 1821–1843’, 287–8, 299–301.
63 Anstey, , ‘Slave trade of the continental powers’, 261; Anstey, , ‘North American slave-carrying trade’, 65; Drescher, , Econocide, 28; Miller, Joseph C., ‘Legal Portuguese slaving from Angola. Some preliminary indications of volume and direction’, Revue française d'histoire d'outre-mer, lxii (1975), 161; Green-Pedersen, , ‘Danish Negro slave Trade’;, 201.
64 Curtin, , Census, 211; and Anstey, , ‘Slave trade of the continental powers’, 261. I have now allowed for the thirteen French ships which sailed for Africa between 1804–6 from Nantes; see Stein, Robert, ‘The Nantes slave traders, 1783–1815’ (Ph.D. thesis, York University, 1975), 271–3. Stein suspects that there were at least as many more ships from other French ports in these years, which could have involved the transfer of a total of 5,000 slaves (personal communication).
65 Anstey, , ‘Slave trade of the continental powers’, 261; and Miller, , ‘Portuguese slaving from Angola’, 161.
66 Alpers, E. A., Ivory and Slaves in East Central Africa (London, 1975), 187–9.
67 Miller, , ‘Portuguese slaving from Angola’, 161. Miller's data on the Portuguese trade in the decade 1811–20 are based on British consular reports from Brazil which were not included in the 1845 Parliamentary Paper. For the years 1811–14 and 1819, the reports show both the number of slaves embarked in Africa and the number delivered in Brazil, while in 1815 and 1816 only slaves delivered are recorded. For 1817, and 1818 and 1820 there were no returns.
68 Miller, , ‘Portuguese slaving from Angola’, 161. Also see Miller, Joseph C., ‘Sources and knowledge of the slave trade in the Southern Atlantic’, unpublished paper read to the Pacific Coast Branch of the American Historical Association, 1976.
69 Alpers, , Ivory and Slaves, 213, 216; and Isaacman, Allen, Mozambique: The Africanization of a European Institution: The Zambezi Prazos, 1750–1902 (Madison, 1972), 92; Vail, Leroy and White, Landeg, Capitalism and Colonialism in Mozambique – A Study of Quelimane District (London, 1980), 6–50.
70 Manning, Patrick, ‘The slave trade in the Bight of Benin, 1640–1890’, in Gemery, and Hogendorn, , Uncommon Market, 117, 137–8. Manning derives his estimate from the shipping data presented in Verger, Pierre, Flux et reflux de la traite des nègres entre le golfe de Bénin et Bahia de Todos os Santos du 17e et 18e siècles (The Hague, 1968), 655, 667.
71 Curtin, , Census, 234, for the volume of imports. These estimates can be checked against exports in the case of the French trade, although the volume of the French trade in the decade 1811–20 presents a problem. Curtin's 1969 estimate was 31,400 slaves imported into the French Caribbean (234); since then Serge Daget has located data on 193 slaving voyages between 1814 and 1820, most of which would have been to French possessions. These voyages may have carried some 61,000 slaves. Curtin's estimate may be too low by half, therefore, if it is assumed that these ships carried an average of 310 slaves per ship and that virtually the whole of French imports was confined to French ships (Eltis, , ‘Transatlantic slave trade 1821–1843’, 287; and Daget, , ‘Illegal French slave trade’, 427, 429). The size of slave cargoes has been determined from the calculations of Eltis for the French trade from 1821–33, when he estimates 338 ships carried 105,000 slaves to the French Caribbean (p. 288). It may be, however, that only half of the French ships stopped at the French islands between 1814 and 1820, if the pattern identified by Eltis for 1821–33 also applied to this earlier period. It is hoped that Daget's work will resolve some of these problems.
72 Eltis, , ‘Export of slaves from Africa’, 423.
73 Northrup, David, ‘The compatibility of the slave and palm oil trades in the Bight of Biafra’, Journal of African History, xvii, iii (1976), 358. It should be noted, however, that there appears to have been no serious economic depression in the Bight of Biafra in the decade after 1810. If Eltis is correct that the trade was much smaller than Northrup claims, then there should have been an economic set back. It may well be, therefore, that Northrup is correct. If he is, then the distributional sample used by Eltis contains a serious error which must be explained.
74 Eltis, , ‘Export of slaves from Africa’, 410–5; Eltis, , ‘Transatlantic slave trade, 1821–1843’, 273–301; and Eltis, ‘Direction and fluctuation of the transatlantic trade, 1844–1867’.
75 For the Dutch trade in some of these years, see La Torre, Joseph R., ‘Wealth surpasses everything: An economic history of Asante, 1750–1874’ (Ph.D. thesis, unpublished, University of California, Berkeley, 1978), 415. La Torre records 1,170 slaves, but I am basing the figures used here on the information gathered from the archives of the Dutch recruitment agency in Kumasi (P. C. Emmer has kindly shared this information with me).
76 Duffy, James, A Question of Slavery (Cambridge, Mass., 1967), 98.
77 Curtin, , Census, 251.
78 Anstey, , ‘British slave trade’, 13.
79 Curtin, , ‘Measuring’, 110–11.
80 See Anstey, , ‘Comment’, 606–7. I wish to thank Professor Curtin for his advice on this matter.
81 Jones, Adam and Johnson, Marion, ‘Slaves from the Windward Coast’, Journal of African History, xxi, i (1980), 17–34.
82 Curtin, , Census, 150, 170. The reassignment of slaves from the Windward Coast to the Bight of Benin accounts for the difference between my estimates and those of Manning (‘Bight of Benin’, 117).
83 Hardyman, J. T., ‘The Madagascar slave-trade to the Americas (1632–1830)’, in Ocean Indien et Mediterranee: Travaux du Sixième Colloque International d'Histoire Maritime et du Deuxieme Congrès de l'Association Historique Internationale de l'Océan Indien (Lisbon, 1963), 516. Also see Campbell, Gwyn, ‘Madagascar and the slave trade, 1810–1895’, Journal of African History, xxii, ii, 1981, 203–27, although Campbell does not make any projections for total exports.
84 Armstrong, James C., ‘The slaves, 1652–1795’, in Elphick, Richard and Giliomee, Hermann, eds., The Shaping of South African Society, 1652–1820 (London, 1979), 77–84. Armstrong accounts for 4,300 slaves imported on ships of the Dutch East India Company, 66 per cent of whom came from Madagascar, between 1652 and 1795. Other slaves were brought in by private merchants, officials trading on their own account, ships returning from the East Indies, and slavers on their way to the Americas. While Armstrong does not hazard an estimate for total imports, it is clear that the number must have been considerably larger than the volume of company imports in order to account for the size of the slave population by the 1790s – estimated at 25,000.
86 Filliot, J. M., La Traite des esclaves vers les Mascareignes au XVIIIe siècle (Paris, 1974), 54, 69; Newitt, M. D. D., The Portuguese Settlement on the Zambezi (London, 1973), 221, where it is estimated that 7,000 slaves per year were exported to the Mascarenes between 1815 and 1830; Alpers, , Ivory and Slaves, 214, where it is noted that the trade between Mozambique and the Mascarenes continued in the 1810s and 1820s; and Renault, François, Libération d'esclaves et nouvelle servitude (Paris, 1976), 158, where the engagé trade is estimated at 45,000 between 1848 and the end of the century.
86 Curtin, , Census, 86–93, 269.
87 Curtin considered the problem of estimating the volume of the trade by comparing data on slave exports with data on slave imports (Census, 217–220). For the period 1761–1810 his calculations for exports – based on shipping data for the non-Portuguese carriers – was 8 per cent lower than his calculations for imports into the Americas (other than Brazil, whose imports were equated with the Portuguese trade). Curtin thought that this discrepancy was more likely to be a result of double counting in the import series than in an underestimation of the volume of exports from Africa, but he warned that a clear solution was not possible on the evidence available in 1969. It is now clear that Curtin was right in suspecting the import data, although he was also low on the export data.
88 Deerr, Noel, The History of Sugar (London, 1950), 11, 284; and Curtin, , Census, 3–13.
89 Average losses at sea between 1680 and 1749, based on a sample of 182 Dutch ships, was 20·5 per cent, while average losses between 1740 and 1795, based on a sample of 130 ships, was 17·4 per cent (Postma, Johannes, ‘Mortality in the Dutch slave trade, 1675–1795’, in Gemery, and Hogendorn, , Uncommon Market, 255). The losses at sea for French vessels in the eighteenth century were 12·2 per cent for ships from the upper Guinea coast (based on a sample of 175 ships), 15·6 per cent for ships from the Gold Coast (based on a sample of 156 ships) and 11·0 per cent from ships from Angola (based on a sample of 101 ships), (Klein, Herbert S. and Engerman, Stanley L., ‘A note on mortality in the French slave trade in the eighteenth century’, in Gemery, and Hogendorn, , Uncommon Market, 269). Klein and Engerman demonstrate that average losses varied with the length of voyage, but for purposes here these variations are not significant. The average losses for 441 ships, including 9 whose coastal origin is unknown (12·9 per cent losses), was 13·1 per cent. Other figures are cited in Curtin, , Census, 277–9: T. F. Buxton recorded losses in the British trade at 875 per cent for 1791 (15,754 slaves) and 17 per cent for 1792 (31,554 slaves). In the Nantes trade from 1748 to 1792, losses averaged 15·2 per cent, and losses were slightly higher in the period before 1748, averaging 16·2 per cent from 1715 to 1775.
90 Average losses at sea between 1821 and 1843 varied with the coastal origin and destination, the major determinant being distance of the voyage. Losses from Senegambia averaged 15·5 per cent (based on a sample of 28 ships); from the Bights of Benin and Biafra, 10·2 per cent (based on a sample of 83 ships); from western-central Africa, 67 per cent (based on a sample of 509 ships); and from southeastern Africa, 16·7 per cent (based on a sample of 167 ships). The average for all ships, including 18 from unspecified origins (18 per cent losses), was 10·1per cent (sample of 805 ships) Eltis, , ‘Transatlantic slave trade, 1821–1843’, 292).
91 Eltis, ‘Direction and fluctuation of the Transatlantic trade, 1844–1867’.
92 Inikori, , ‘Assessment of Curtin and Anstey’, 202–4; and Inikori, , ‘Rejoinder’, 617–22.
93 Vilar, Vila, Comercio de esclavos, 206–9.
94 Fogel, and Engerman, , Time on the Cross, Evidence and Methods, 30–1.
95 Eltis, ,‘Transatlantic slave trade, 1821–1843’, 291, where Eltis estimates that his total for 1821–43 is 30 per cent higher than Curtin's figure, but my calculation suggests that Eltis is about 19 per cent higher.
96 Curtin, , Census, 268.
97 Rodney, Walter, How Europe Underdeveloped Africa (London, 1972).
98 Fage, , History of Africa, 244–88.
99 Inikori, , ‘Introduction’, 13–60.
100 Lovejoy, Transformations in Slavery.
101 Reynolds, Edward, Stand the Storm: A History of the Atlantic Slave Trade (New York, 1982), does not attempt a new estimate for the volume of the trade, and instead relies on Curtin's study. Nonetheless, his analysis of the impact of the slave trade on Africa is an important aspect of his study.
1 An earlier version of this article was presented at the African Studies Association annual meeting, Bloomington, Indiana, 1981. I wish to thank David Eltis, Stanley Engerman, Joseph C. Miller, Henry Gemery, P. C. Emmer, Patrick Manning, Robert Stein, Philip D. Curtin, and Russell Chace for their comments and assistance at various stages of this synthesis. While I am solely responsible for any remaining errors, their efforts were crucial in catching more than a few mistakes. I do not wish to hold them responsible for my conclusions, but in more ways than is usually the case, this synthesis was a group effort.
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