the Inflection , Reflection , and Colours of Light. 275 
formed of the hole distended like those of the sun, as I have 
often found ; and the same holds of inflection. Why does cut- 
ting a body to pieces not alter its colours ? This only changes 
the position of masses of particles, not of the particles them- 
selves ; but if by bruising them we change their magnitude 
and position, we change also their colour ; thus the leaves of 
vegetables bruised in a mortar, many paints powdered, &c. 
Why do many bodies change colours when viewed in dif- 
ferent positions ? Because they reflect two colours, or more, of 
each image to different quarters ; and it matters not whether 
their position with respect to us or our position with respect 
to them be changed. How do bodies appear coloured by 
transmitted light ? Because the foregoingreasonings apply also 
to the flexion of the rays in their passage through the parts of 
bodies. These observations appear to me to furnish a very 
simple solution of the problem. I shall endeavour, in a future 
communication, to confirm what has been said, by other re- 
marks and experiments ; for it would be tedious, and perhaps 
superfluous, to illustrate what has been said by figures and de- 
monstrations.* 
Pursuant to these remarks, it will not be difficult to account 
for the rings of colours of thin plates by reflection, as we be- 
fore did those of thick plates by flexion ; -f- indeed those formed 
in the experiment of the two lenses, supposed by Newton to 
* It is obvious that the different refrangibility of the rays will not account for the 
bright and distinct colours of bodies : if the refracting angle of a prism be continually 
diminished, till, for example, it is equal to one of a minute, the refraction will produce 
no sensible colours ; indeed almost every piece of plane glass has its sides in a small 
degree inclined to one another, and yet no colours are formed; much less then will re- 
fraction through the infinitely smaller- parts of bodies, produce separation of the rays. 
f Page 260 of this paper. 
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