An Account of Some Cases of the Production ofColours, Not Hitherto Described. Thomas Young.

                                All these circumstances are sufficient to satisfy us with respect 
to the truth of the explanation; and it is still more con-
firmed by the effect of inclining the plates to the direction 
of the light; for <s>[text]<\s> for then, instead of dilating, like the <s>ring 
of the <\s> colours of thin plates, these rings contract: and this 
is the obvious consequence of an increase of the length of 
the paths of the light, which now traverses both mediums,
obliquely; and the effect is every where the same as that 
of a thicker plate.
It must however be observed, that the colours are not 
produced in the whole light that is transmitted through the 
medium: a small portion only of each pencil passing through the water, contiguous to 
the <s>common surface <\s> edges of the particle, is sufficiently coin-
cident with the light transmitted by the neighbouring 
portions of air, to produce the necessary interference: and 
it is easy to show that, on account of the natural conca-
vity of the surface of each portion of the fluid adhering 
to the two pieces of glass, a considerable portion of 
the light which is beginning <s>about <\s> to pass through the water, will be 
dissipated laterally by reflection at its entrance, and that 
much of the light passing through the air will be scattered 
by refraction at the second surface. For these reasons, the 
fringes are seen <s>even <\s> when the plates are not directly inter-
posed between the eye and the luminous object, and, on 
account of the absence of foreign light, even more distinctly 
than when they are in the same right line with that 
object. And if we remove the plates to a considerable