In 1729 the duty was reduced to two pounds. This duty continued in force for a generation, satisfactory partly because the opposition to importing negroes seems to have been less strong, partly because white servants proved to be cheaper and more adapted to industrial demands.[20] The newspaper advertisements announce the arrival of many more cargoes of servants than of negroes; this notwithstanding the fact that white servants frequently ran away, often to enlist in the wars. Referring to this fact a message from the Assembly to the governor says that while the King has seemed to desire the importation of servants rather than of negroes, yet the enlistment acts make such property so precarious, that it seems to depend on the will of the servant and the pleasure of the officer.[21] Nevertheless the number of negroes brought in steadily dwindled. By 1750 importation had nearly ceased.[22] A few years later the great efforts made in the last French and Indian War caused loud complaints again about enlisting servants. It was feared that people would be driven to the necessity of providing themselves with negro slaves, as property in them seemed more secure. This is probably just what occurred, for the increase of negroes is said to have been alarming.[23] As a result restrictive legislation was tried again in 1761, when the duty was made ten pounds. The law was carried only after considerable effort. While the bill was in the hands of the governor a petition was sent to him, signed by twenty-four merchants of Philadelphia, who set forth the scarcity and high price of labor, and their need of slaves. After two months' contest the bill was passed. One provision of the act was that a new settler need not pay the duty if he did not sell his slave within eighteen months.[24] In 1768 this act was renewed. In 1773 it was made perpetual, the former law having been found to be of great public utility; but the duty was raised to twenty pounds. Once more the act became law by lapse of time.[25] The act of 1773 was the last one which the Assembly passed to limit the importation of negroes. Not only was the duty sufficiently high, now, but its presence was hardly needed.[26] A silent but powerful movement was overthrowing slavery in Pennsylvania; and in a short time the outbreak of the Revolutionary War brought the traffic to an end. Shortly thereafter, in 1780, the state did what England had never permitted while she held authority: forbade the importation of slaves entirely.[27]