~ ee 
7 “owt Refilaiion® of. + fy | 357 
" the solar light entering a aa chafiiber, I fixed the lens thus adjust- 
ed in the isolate rays, which were refracted in their passage 
Breet the lens, and made to converge to a focal point at precisely 
ty four i from the glass. The lens was then fixed in the 
violet rays, 1 
h having passed through it, converged to a focus at 
our inches from it. The orange, yellow, green, 
> passed separately through ‘the lens, and 
A o one focus. A bi-convex glass, whose focal 
distance i is four feet, was subsequently employed, and gave results — 
Serupulously analogous to those already stated : all the differently 
= rays converging at the same distance from the lens. 
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2. 
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a 
Double concave glasses were used to determine whether the di- 
ent rays of the different colors would form circles of equal. diam- 
eters, at the same distance from the lens. The circumference of 
the circle formed by the divergency of the red rays was. accurately 
marked with a pencil on letter paper, and the cirele produced by the 
violet’ rays was found to have, at an equal distance, the same diame- 
ter. These experiments are obvious and simple, and they go to es- 
: — that the rays of all colors are equally refrangible. 
_ If we admit'that the several colorific rays are endowed with dif- 
rent degrees of refrangibility, we must be prepared to admit the 
3 ; - fling results, as the necessar y consequence of such a property. 
1. A beam of white light, in passing through a diaphanous modee 
umn of equal thickness, as a plate of glass, with parallel surfaces, 
Would undergo analysis, and the colors would appear in the order of 
their refrangibilities. ~ 
_» 2. Bodies viewed through | diffétent colors of light ‘call appear 
of different magnitudes ; for the focal distance of the crystalline lens 
Would vary, according to the refrangibility of the rays. 
8. Adouble convex elass would have seven foci ; ; for the violet 
rays, being most refrangible, would converge soonest to a focus, and 
the re ays, being least so, would fo the most distant one. If, 
Ps: there ore, the violet focus were rec ed on paper, it would be seen 
Strrounded with six circles of colored light, of which the red “ou *% 
~ form the external, 
4. The same chromatic circles would appear, if solar light were 
transmitted through a double concave glass ; with this difference, that 
in the latter case, the center would be formed of the least refrangible 
or red ray, and the iin of the violet. - 
46 
oL. XX.—No. 
