the Inflection, Reflection, and Colours of Light. 271 
are so *many irregular specula, of great curvature ; the images 
are therefore distorted and broken, just as a candle, &c. appears 
broken and coloured when viewed through a piece of irregular 
crystal, such as the bottom of a wine glass. If we look atten- 
tively at any object exposed in the light of the sun, provided 
it be not polished, we shall see its surface mottled with various 
points of colours, from the specular nature of its minute par- 
ticles. If we look towards the sun, with a hat on our head, 
held down, so that the sun's direct light may not fall on our 
eyes, but on the hairs of the hat, and be reflected, we shall 
see a variety of lively colours darting in all directions from 
those hairs ; and we may easily satisfy ourselves that they are 
not the consequence of flexion, by trying the same thing with 
unpolished threads, in which case they do not appear, provided 
the threads be not very small. In the same manner we may 
account for the colours of spider webs, of different cloths which 
change their colours when their position is altered, and of some 
fossils which appear of different streaks of colours when held 
in the light, such as the fire marble of Saxony, See. All these 
bodies having surfaces of a fibrous structure, each fibre reflects 
and decompounds the rays. 
4. The consideration of the foregoing phsenomena inclined 
me to think, that upon the principles which have been laid 
down, the colours of natural bodies may be explained. The 
celebrated discovery of Newton, that these depend on the 
thickness of their parts, is degraded by a comparison with his 
hypothesis of the fits of rays and waves of aether. Delighted 
and astonished by the former, we gladly turn from the latter ; 
and unwilling to involve in the smoke of unintelligible theory 
so fair a fabric, founded on strict induction, we wish to find 
