An Account of a Remarkable Imperfection of Sight. In a Letter from J. Scott to the Rev. Mr. Whisson, of Trinity College, Cambridge. Communicated by the Rev. Michael Lort, B. D. F. R. S.

XXVII. An Account of a remarkable Imperfection of Sight. In a Letter from J. Scott to the Rev. Mr. Whisson, of Trinity College, Cambridge. Communicated by the Rev. Michael Lort, B. D. F. R. S. TO SIR JOHN PRINGLE, BART. P. R. S. SIR, Read April 9, 1778. A FRIEND of mine, the rev. Mr. Whisson, of Trinity College, Cambridge, being acquainted with a gentleman in Lincolnshire, who labours under an inability of distinguishing colours similar to that of which an account is given in the last volume of the Philosophical Transactions, did write to him for some particular information concerning this infirmity. The answer which Mr. Whisson received I have now, by his permission, the honour of transmitting to you, to be communicated to the Royal Society, if you shall think it worthy their attention. I am, &c. MICHAEL LORT. TO THE REV. MR. WHISSON. REV. SIR, I RECEIVED your favour in due time. I should have given you my answer sooner, but have been greatly afflicted with the gout. I am very willing to inform you (and take your inquiry as a favour) of my inability concerning colours, as far as I am able from my own common observation. It is a family failing: my father has exactly the same impediment: my mother and one of my sisters were perfect in all colours: my other sister and myself alike imperfect: my last mentioned sister has two sons both imperfect; but she has a daughter who is very perfect: I have a son and daughter, who both know all colours without exception; and so did their mother: my mother's own brother had the like impediment with me, though my mother, as mentioned above, knew all colours very well. Now I will inform you what colours I have the least knowledge of. I do not know any green in the world; a pink colour and a pale blue are alike, I do not know one from the other. A full red and a full green the same, remarkable Imperfection of Sight. I have often thought them a good match; but yellows (light, dark, and middle) and all degrees of blue, except those very pale, commonly called sky, I know perfectly well, and can discern a deficiency, in any of those colours, to a particular nicety: a full purple and deep blue sometimes baffle me. I married my daughter to a genteel, worthy man a few years ago; the day before the marriage he came to my house, dressed in a new suit of fine cloth cloaths. I was much displeased that he should come (as I supposed) in black: said, He should go back to change his colour. But my daughter said, No, no; the colour is very genteel; that it was my eyes that deceived me. He was a gentleman of the law, in a fine rich claret-coloured dress, which is as much a black to my eyes as any black that ever was dyed. She has been married several years; no child living, and my son is unmarried; so how this impediment may descend from me is unknown. I have a general good satisfaction in the midst of this my inability; can see objects at a distance when I am on travel with an acquaintance, and can distinguish the size, figure, or space, equal to most, and I believe as quick, colour excepted. My My business was behind a counter many years, where I had to do with variety of colours. I often, when alone, met with a difficulty; but I commonly had a servant in the way to attend me, who made up my deficiency. I have been now seven years from trade. My eyes, thank God, are very good at discerning men and things. If your learned Society can search out the cause of this very extraordinary infirmity, and find a method for an amendment, you will be so obliging to acquaint me. I am, &c. J. SCOTT.