112 Count Rumford’s Account of some 
the same glass nearly destroyed the colours of both the shadows : 
and three sheets changed the shadow which was originally 
yellow to blue, and that which was blue to a purplish yellow 
colour. 
When the beam of daylight was made to pass through a 
sheet of blue glass, the colours of the shadows, the yellow as 
well as the blue, were improved and rendered in the highest 
degree clear and brilliant; but when the blue glass was placed 
before the candle, the colours of the shadows were very much 
impaired. . 
In order to see what would be the consequence of rendering 
the candle light of a still deeper yellow, I interposed before it 
a sheet of yellow or rather orange-coloured glass, when a very 
unexpected and most beautiful appearance took place ; the 
colour of the yellow shadow was changed to orange, the blue 
shadow remained unchanged, and the whole surface of the 
paper appeared to be tinged of a most beautiful violet colour, ap- 
proaching to a light crimson or pink ; almost exactly the same 
hue as I have often observed the distant snowy mountains and 
valleys of the Alps to take about sunset. Is it not more than 
probable that this hue is in both cases produced by nearly the 
same combinations of coloured light? in the one case, it is 
the white snow illuminated at the same time by the purest 
light of the heavens, and by the deep yellow rays from the 
west ; and in the other, it is the white paper illuminated by 
broad daylight, and by the rays from a burning candle ren- 
dered still more yellow by being transmitted through the 
yellow glass. The beautiful violet colour which spreads itsel 
over the surface of the paper will appear to the greatest ad- 
vantage, if the pane of orange-coloured glass be held m such 
