Details of characteristic outfit, cargo, and expectations in the New England branch of trade may be had from an estimate made in 1752 for a projected voyage.[41] A sloop of sixty tons, valued at L300 sterling, was to be overhauled and refitted, armed, furnished with handcuffs, medicines and miscellaneous chandlery at a cost of L65, and provisioned for L50 more.  Its officers and crew, seven hands all told, were to draw aggregate wages of L10 per month for an estimated period of one year.  Laden with eight thousand gallons of rum at 1_s. 8_d_. per gallon and with forty-five barrels, tierces and hogsheads of bread, flour, beef, pork, tar, tobacco, tallow and sugar—­all at an estimated cost of L775—­it was to sail for the Gold Coast.  There, after paying the local charges from the cargo, some 35 slave men were to be bought at 100 gallons per head, 15 women at 85 gallons, and 15 boys and girls at 65 gallons; and the residue of the rum and miscellaneous cargo was expected to bring some seventy ounces of gold in exchange as well as to procure food supplies for the westward voyage.  Recrossing the Atlantic, with an estimated death loss of a man, a woman and two children, the surviving slaves were to be sold in Jamaica at about L21, L18, and L14 for the respective classes.  Of these proceeds about one-third was to be spent for a cargo of 105 hogsheads of molasses at 8_d_. per gallon, and the rest of the money remitted to London, whither the gold dust was also to be sent.  The molasses upon reaching Newport was expected to bring twice as much as it had cost in the tropics.  After deducting factor’s commissions of from 2-1/2 to 5 per cent. on all sales and purchases, and of “4 in 104” on the slave sales as the captain’s allowance, after providing for insurance at four per cent. on ship and cargo for each leg of the voyage, and for leakage of ten per cent. of the rum and five per cent. of the molasses, and after charging off the whole cost of the ship’s outfit and one-third of her original value, there remained the sum of L357, 8s. 2d. as the expected profits of the voyage.

[Footnote 41:  “An estimate of a voyage from Rhode Island to the Coast of Guinea and from thence to Jamaica and so back to Rhode Island for a sloop of 60 Tons.”  The authorities of Yale University, which possesses the manuscript, have kindly permitted the publication of these data.  The estimates in Rhode Island and Jamaica currencies, which were then depreciated, as stated in the document, to twelve for one and seven for five sterling respectively, are here changed into their approximate sterling equivalents.]

As to the gross volume of the trade, there are few statistics.  As early as 1734 one of the captains engaged in it estimated that a maximum of seventy thousand slaves a year had already been attained.[42] For the next half century and more each passing year probably saw between fifty thousand and a hundred thousand shipped.  The total transportation from first to last may well have numbered more than five million souls.  Prior to the nineteenth century far more negro than white colonists crossed the seas, though less than one tenth of all the blacks brought to the western world appear to have been landed on the North American continent.  Indeed, a statistician has reckoned, though not convincingly, that in the whole period before 1810 these did not exceed 385,500[43]