36 On the Vision of Colours. 
I seldom fail to distinguish purple from blue; but 
should hardly suspect purple to be a compound of 
blue and red. The difference between- day-light 
and candle-light is not material. 
MISCELLANEOUS OBSERVATIONS, 
Colours appear to me much the same by moon- 
light, as they do by candle-light. * 
Colours viewed by lightning appear the same as 
by day-light; but whether exactly so, I have not as- 
certained. | 
Colours seen by electric light appear to me the 
same as by day-light. That is, pink appears blue, 
&e. 
Colours viewed through a transparent sky-blue 
liquid, by candle-light, appear to me as well as to 
others the same as by day-light. 
Most of the colours called drabs appear. to me 
the same by day-light and candle-light. 
A light drab woollen cloth seems to me to re- 
semble a light green by day. These colours are, 
however, easily distinguished by candle-light, as the 
latter becomes tinged with blue, which the former 
does not. I have frequently seen colours of the drab 
kind, said to be nearly alike, which appeared to me 
very different. wedi . 
* Mr. Boyle observed colours by moon-light to differ 
from those by day-light, Priestley on Vision, p. 145. 
a ot 
