To the poem is affixed a frontispiece, in which the Negro is represented.

He is made to stand in an attitude of the most earnest address to Heaven, in the course of which, with the fatal dagger in his hand, he breaks forth in the following words: "To you this unpolluted blood I poor, To you that spirit, which ye gave, restore." This poem, which was the first ever written expressly on the subject, was read extensively; and it added to the sympathy in favour of suffering humanity, which was now beginning to show itself in the kingdom.
About this time the first edition of the Essay on Truth made its appearance in the world.

Dr.Beattie took an opportunity, in this work, of vindicating the intellectual powers of the Africans from the aspersions of Hume, and of condemning their slavery as a barbarous piece of policy, and as inconsistent with the free and generous spirit of the British nation.
In the year 1774, John Wesley, the celebrated divine, to whose pious labours the religious world will be long indebted, undertook the cause of the poor Africans.

He had been in America, and had seen and pitied their hard condition.

The work which he gave to the world in consequence, was entitled Thoughts on Slavery.