Mr Dal ton on the Vision of Colours. 91 



shade, or defect of light ; after that the orange, yellow, and 

 green seern one colour, which descends pretty Uniformly from 

 an intense to a rare yellow, making what I should call different 

 shades of yellow. The difference between the green part and 

 the blue part is very striking to my eye : they seem to be 

 strongly contrasted. That between the blue and purple is 

 much less so. The purple appears to be blue much darkened 

 and condensed. In viewing the flame of a candle by night 

 through the prism, the appearances are pretty much the same, 

 except that the red extremity of the image appears more vivid 

 than that of the solar image. 



I now proceed to state the results of my observations on the 

 colours of bodies in general, whether natural or artificial, both 

 by day-light and candle-light. I mostly used ribbands for 

 the artificial colours. 



Redby day-light. — Under this head I include crimson, scar- 

 let, red, and pink. All crimsons appear to me to consist chiefly 

 of dark blue ; but many of them seem to have a strong tinge 

 of dark brown. I have seen specimens of crimson, claret, and 

 mud, which were very nearly alike. Crimson has a grave ap- 

 pearance, being the reverse of every shewy and splendid co- 

 lour. Woollen yarn dyed crimson or dark blue is the same to 

 mc. Pink seems to be composed of nine parts of light blue, 

 and one of red, or some colour which has no other effect than 

 to make the light blue appear dull and faded a little. Pink 

 and light blue, therefore, compared together, are to be distin- 

 guished no otherwise than as a splendid colour from one that 

 has lost a little of its splendour. Besides the pinks, roses, &c. 

 of the gardens, the following British flora appear to me blue ; 

 namely, Statice Armeriu, Trifolium pratense, Lychnis Flos- 

 cuculi, Lychnis dioica, and many of the Gerania. The co- 

 lour of a florid complexion appears to me that of a dull, 

 opaque, blackish blue, upon a white ground. A solution of 

 sulphate of iron in the tincture of galls (that is, dilute black 

 ink) upon white paper, gives a colour much resembling thai 

 of a florid complexion. It has no resemblance of the colour 

 of blood. Red and .sen, let form a genus with mc totally 

 different from pink. -My idea of red I obtain from vcrmi/iou, 

 minium, sealing-wax, wafer*, a soldier's uniform, Szc, These 



