LVI. A discourse on the locus for three and four lines celebrated among the ancient geometers, by H. Pemberton, M. D. R. S. Lond. Et R. A. Berol. S. In a letter to the Reverend Thomas Birch, D. D. Secretary to the Royal Society

Sir, My worthy friend, and associate in my early studies, the collector of the late Mr. Robins's mathematical tracts, thought it conducive to a more compleat vindication of the memory of his friend against an insinuation prejudicial to his candour, to make some mention of the course, I took in my early mathematical pursuits, and how soon I became attached to the ancient manner of treating geometrical subjects. This gave occasion to my looking into some of my old papers, amongst which I found a discussion of the problem relating to the locus ad tres & quatuor lineas celebrated among the ancients, which I the communicated to a friend or two, whose sentiments of those ancient sages were the same with mine. What I had drawn up on this subject is contained in the papers, I herewith put into your hands, which if you shall think worthy of being laid before our honourable society, they are intirely at your disposal.