After supper I accompanied him to his apartment, and at my request he dictated to me an argument in favour of the negro who was then claiming his liberty, in an action in the Court of Session in Scotland.  He had always been very zealous against slavery in every form, in which I, with all deference, thought that he discovered ‘a zeal without knowledge.’  Upon one occasion, when in company with some very grave men at Oxford, his toast was, ’Here’s to the next insurrection of the negroes in the West Indies.’  His violent prejudice against our West Indian and American settlers appeared whenever there was an opportunity.  Towards the conclusion of his Taxation no Tyranny, he says, ’how is it that we hear the loudest yelps for liberty among the drivers of negroes?’

When I said now to Johnson, that I was afraid I kept him too late up.  ‘No, Sir, (said he,) I don’t care though I sit all night with you.’  This was an animated speech from a man in his sixty-ninth year.

Had I been as attentive not to displease him as I ought to have been, I know not but this vigil might have been fulfilled; but I unluckily entered upon the controversy concerning the right of Great-Britain to tax America, and attempted to argue in favour of our fellow-subjects on the other side of the Atlantick.  I insisted that America might be very well governed, and made to yield sufficient revenue by the means of influence, as exemplified in Ireland, while the people might be pleased with the imagination of their participating of the British constitution, by having a body of representatives, without whose consent money could not be exacted from them.  Johnson could not bear my thus opposing his avowed opinion, which he had exerted himself with an extreme degree of heat to enforce; and the violent agitation into which he was thrown, while answering, or rather reprimanding me, alarmed me so, that I heartily repented of my having unthinkingly introduced the subject.  I myself, however, grew warm, and the change was great, from the calm state of philosophical discussion in which we had a little before been pleasingly employed.

We were fatigued by the contest, which was produced by my want of caution; and he was not then in the humour to slide into easy and cheerful talk.  It therefore so happened, that we were after an hour or two very willing to separate and go to bed.

On Wednesday, September 24, I went into Dr. Johnson’s room before he got up, and finding that the storm of the preceding night was quite laid, I sat down upon his bed-side, and he talked with as much readiness and good-humour as ever.  He recommended to me to plant a considerable part of a large moorish farm which I had purchased, and he made several calculations of the expence and profit:  for he delighted in exercising his mind on the science of numbers.  He pressed upon me the importance of planting at the first in a very sufficient manner, quoting the saying ‘In bello non licet bis errare:’  and adding, ’this is equally true in planting.’