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 stat