Negroes were not numerous. There remains rather scant evidence of their presence in any considerable number, but authentic record of certain instances. It is found, for example, that as early as 1639 a convict was sentenced to South River, as the Delaware was then called, to serve out his time with the Negroes.[1130] This is the earliest record found; though frequent mention is made of them after this date. In 1664, the West India Company agreed to furnish about fifty Negroes to work in the lowlands on the Delaware River.[1131] This is the earliest explicit record that is found of trafficking in Negroes in Pennsylvania. The slave trade, thus begun by the Dutch Company, was continued, now rising, now falling, till the final abolition of slavery in 1780.[1132] The law of 1780, which provided for a gradual abolition, was subjected to such frequent evasion that in 1788 it became necessary to pass another for its clarification and enforcement.[1133] By the middle of the seventeenth century, the importation of slaves had become a part of the regular work of the merchants of Philadelphia, with the exception of a few conscientious Quakers who refused to profit thereby. Records of the end of the century indicate that the number of Negroes had by that time become very considerable, though no exact figures are obtainable.[1134] [Sidenote: Opposing factors] But it is not to be assumed that because the slave trade began thus early and continued to grow, it did so without meeting any opposition. In fact it is probably due to a few years of opposition by various factors, which are here only mentioned briefly, that the slave trade did not become as prodigious in Pennsylvania as in other states, and that she was the first to pass an abolition law against it.[1135] Chief among the factors which opposed the increase of Negro serfdom were these: (1) the conscientious scruples of Friends in reference to the traffic;[1136] (2) the objection on the part of the German inhabitants (partially as Quakers, but not entirely);[1137] and, (3) the dissatisfaction caused among White laborers by the enforced competition of the Negroes.[1138] [Sidenote: Restrictive legislation 1700, 1705, 1712] [Sidenote: Slack demand for slaves indicated]