Wallis, in his _System of the Laws of Scotland_, maintains, that "neither men nor governments have a right to sell those of their own species. Men and their liberty are neither purchaseable nor saleable." And, after arguing the case, he says, "This is the law of nature, which is obligatory on all men, at all times, and in all places.--Would not any of us, who should be snatched by pirates from his native land, think himself cruelly abused, and at all times entitled to be free? Have not these unfortunate Africans, who meet with the same cruel fate, the same right? Are they not men as well as we? And have they not the same sensibility? Let us not, therefore, defend or support an usage, which is contrary to all the laws of humanity." In the year 1750, the reverend Griffith Hughes, rector of St. Lucy, in Barbados, published his Natural History of that island. He took an opportunity, in the course of it, of laying open to the world the miserable situation of the poor Africans, and the waste of them by hard labour and other cruel means, and he had the generosity to vindicate their capacities from the charge, which they who held them in bondage brought against them, as a justification of their own wickedness in continuing to deprive them of the rights of men. Edmund Burke, in his account of the European settlements, (for this work is usually attributed to him,) complains "that the Negroes in our colonies endure a slavery more complete, and attended with far worse circumstances, than what any people in their condition suffer, in any other part of the world, or have suffered in any other period of time. Proofs of this are not wanting. The prodigious waste, which we experience in this unhappy part of our species, is a full and melancholy evidence of this truth." And he goes on to advise the planters, for the sake of their own interest, to behave like good men, good masters, and good Christians, and to impose less labour upon their slaves, and to give them recreation on some of the grand festivals, and to instruct them in religion, as certain preventives of their decrease. An anonymous author of a pamphlet, entitled, _An Essay in Vindication of the Continental Colonies of America_, seems to have come forward next. Speaking of slavery there, he says, "It is shocking to humanity, violative of every generous sentiment, abhorrent utterly from the Christian religion.--There cannot be a more dangerous maxim than that necessity is a plea for injustice, for who shall fix the degree of this necessity? What villain so atrocious, who may not urge this excuse, or, as Milton has happily expressed it, And with necessity, The tyrant's plea, excuse his devilish deed?