The feeling among some of the Friends was extraordinary at this time. They went from one slaveholder to another expostulating, persuading, entreating. It was then that the saintly John Woolman did his work; but he was only the most distinguished among many others. It is hardly possible to read over the records of any Friends' meeting for the next thirty years without finding numerous references to work of this character; and in more than one journal of the period mention is made of the obstacles encountered and the expedients employed.[182] The results of their efforts were far-reaching. Many Friends who would have scrupled to buy more slaves, and who were convinced that slave-holding was an evil, yet retained such slaves as they had, through motives of expediency, and also because they believed that negroes held in mild bondage were better off than when free. Against this temporizing policy the reformers fought hard, and aided by the decision of the Yearly Meeting that slaveholders should no longer participate in the affairs of the Society, carried forward their work with such success that within one more generation slavery among the Friends in Pennsylvania had passed away. During the period, then, from 1750 to 1780 manumission among the Friends became very frequent. Many slaves were set free outright, their masters assuming the liability required by law. Others were manumitted on condition that they would not become chargeable.[183] Some owners gave promise of freedom at the end of a certain number of years, considering the service during those years an equivalent for the financial obligation which at the end they would have to assume.[184] Often the negro was given his liberty on condition that at a future time he would pay to the master his purchase price.[185] In 1751 a writer said that numerous negroes had gained conditional freedom, and were wandering around the country in search of employment so as to pay their owners. The magistrates of Philadelphia complained of this as a nuisance.[186] Just how many slaves gained their freedom during this period it is impossible to say. The church records mention them again and again; and they become, what they had not been before, the occasion of frequent notice and serious speculation.[187] Other people began now to follow the Friends' example,[188] and the belief in abstract principles of freedom aroused by the Revolutionary struggle gave further impetus to the movement.[189] In every quarter, now, manumissions were constantly being made.[190] Any estimate as to how many negroes, servants and free, there were in Pennsylvania by 1780 must be largely a conjecture, but it is perhaps safe to say that there were between four and five thousand.[191]