As early as 1698 the slave-trade to South Carolina had reached such
proportions that it was thought that "the great number of negroes which
of late have been imported into this Collony may endanger the safety
thereof." The immigration of white servants was therefore encouraged by
a special law.[10] Increase of immigration reduced this disproportion,
but Negroes continued to be imported in such numbers as to afford
considerable revenue from a moderate duty on them. About the time when
the Assiento was signed, the slave-trade so increased that, scarcely a
year after the consummation of that momentous agreement, two heavy duty
acts were passed, because "the number of Negroes do extremely increase
in this Province, and through the afflicting providence of God, the
white persons do not proportionately multiply, by reason whereof, the
safety of the said Province is greatly endangered."[11] The trade,
however, by reason of the encouragement abroad and of increased business
activity in exporting naval stores at home, suffered scarcely any check,
although repeated acts, reciting the danger incident to a "great
importation of Negroes," were passed, laying high duties.[12] Finally,
in 1717, an additional duty of £40,[13] although due in depreciated
currency, succeeded so nearly in stopping the trade that, two years
later, all existing duties were repealed and one of £10 substituted.[14]
This continued during the time of resistance to the proprietary
government, but by 1734 the importation had again reached large
proportions. "We must therefore beg leave," the colonists write in that
year, "to inform your Majesty, that, amidst our other perilous
circumstances, we are subject to many intestine dangers from the great
number of negroes that are now among us, who amount at least to
twenty-two thousand persons, and are three to one of all your Majesty's
white subjects in this province. Insurrections against us have been
often attempted."[15] In 1740 an insurrection under a slave, Cato, at