DALTOX. 55 



thought of either becoming a barrister or entering the medical 

 profession. Happily for science, and for himself too, he did 

 neither. What is erroneously called a casualty proved the 

 turning-point of his scientific destiny. In the year 1793, Mr. 

 Barnes asked Mr. Gtough to recommend a suitable teacher for 

 mathematics in the New College of Manchester. He recom- 

 mended Dalton, who was accordingly elected. He lived in the 

 establishment, and taught mathematics for six years ; publish- 

 ing during this time his Meteorological Observations and Essays. 

 In 1794, Dalton became a member of the Literary and 

 Philosophic Society of Manchester, inaugurating his connec- 

 tion with that learned body by reading a paper on ' Extra- 

 ordinary Facts relating to the Vision of Colours.' The fact 

 is, Dalton was a subject of the peculiar visual defect to which 

 the term of colour blindness has subsequently been given. He 

 did not see colours as people usually see them. * I can,' says 

 he, ' see two. or at the utmost three, distinctions in the solar 

 spectrum; these I should call yellow and blue, or yellow, 

 blue, and purple. Yellow and blue make a contrast to my 

 eyes; blue and purple differ more in degree than in kind. 

 Pink appears by daylight to be sky-blue, a little faded ; by 

 candle-light it assumes an orange or yellowish appearance. 

 Crimson appears muddy blue by day; and crimson woollen 

 yarn is much about the same as dark blue. Red and scarlet 

 have a more vivid and flaming appearance by candle-light 

 than by day-light. To me there is not much difference of 

 colour between a stick of red sealing-wax and grass by day. 

 Dark green woollen cloth seems a muddy red, much darker 

 than grass, and of a very different colour. Coats, gowns, 

 &c. appear to me frequently to be badly matched with lin- 

 ings when others say they are not. On the other hand, I 

 should match crimson with claret or mud ; pinks with light 

 blues ; browns with reds, and drabs with greens. The colour 

 of a florid complexion is dusky blue.' Dusky blue for a lady's 

 face! 



