In his more important legal causes Boswell had recourse to Dr. Johnson’s assistance. At Ashbourne he asked help in a case of importance. Joseph Knight, a negro, having been brought to Jamaica in the usual course of the slave trade, was purchased by a Scottish gentleman in the island, who afterwards returned to Scotland. Soon after his arrival Knight claimed his freedom, and brought an action to enforce it.[62] The case was now pending, and Boswell induced Dr. Johnson to dictate an argument on the negro’s behalf. In recording it he is careful to add that he was personally an upholder of the slave trade. He writes:— “I record Dr. Johnson’s argument fairly upon this particular case; where, perhaps, he was in the right. But I beg leave to enter my most solemn protest against his general doctrine with respect to the slave trade. For I will resolutely say that his unfavourable notion of it was owing to prejudice and imperfect or false information. The wild and dangerous attempt which has for some time been persisted in to obtain an Act of our Legislature to abolish so very important and necessary a branch of commercial interest must have been crushed at once, had not the insignificance of the zealots, who vainly took the lead in it, made the vast body of planters, merchants, and others, whose immense properties are involved in that trade, reasonably enough suppose that there could be no danger. The encouragement which the attempt has received excites my wonder and indignation; and though some men of superior abilities have supported it, whether from a love of temporary popularity when prosperous, or a love of general mischief when desperate, my opinion is unshaken. To abolish a _status_ which in all ages God has sanctioned and man has continued, would not only be robbery to an innumerable class of our fellow-subjects, but it would be extreme cruelty to the African savages, a portion of whom it saves from massacre, or intolerable bondage in their own country, and introduces into a much happier state of life, especially now when their passage to the West Indies, and their treatment there, is humanely regulated. To abolish that trade would be to— “——Shut the gates of mercy on mankind.” The political success of Edmund Burke induced Boswell to indicate his readiness to co-operate with him in regard to the American colonies. To Mr. Burke he wrote as follows:— “_Edinburgh, March 3, 1778._