Many attempts have been made to color with ruby or other colors gas shades, so as to throw on surrounding objects the color of the glass; but in no case has the ray of light passing through colored glass, to refract the shade, been successful.

But when a ray of solar light is passed through a colorless prism, it is refracted, and forms, when thrown on a wall or screen, a broad band of colored light,—red, orange, yellow, green, blue, indigo, and violet,—which is known as the prismatic or solar spectrum.

ARTIFICIAL DIAMONDS.

We find a report in French journals that M. Gannal has succeeded in obtaining crystals, having all the property of the diamond, through the mutual reaction of phosphorus water and bisulphide of carbon upon each other for the space of fifteen weeks.

The crystals were found to be so hard that no file would act upon them. They cut glass like ordinary diamonds, and scratched the hardest steel. In brilliancy and transparency they were in no way inferior to the best jewels, and some possessed a lustre surpassing that of most real stones.

For reference we record the cost of materials for flint-glass, say in 1840 to 1845, as follows:—

Litherage, or red lead, cost6½cts. per lb.
Pearlash,6 " "
Nitre,6 " "
Silex,0½" "

Present price, 1864:—

Red lead,21 cts. per lb.
Pearlash,17 " "
Nitre,6 " "
Silex,0¾" "

We now refer to the early introduction of the manufacture of glass into England. The English manufacturers, like ourselves, had to struggle with the various evils incident to the introduction of a new art. France and Germany, from their long experience in the making of glass, were enabled for a long time to undersell the English manufacturer in his own market.