permanent Flint Glass is that which by the greatest caloric can be made to contain the largest proportion of silex; but it is not so well calculated for chandeliers, (which should be more highly refractive,) nor for optical purposes, as for ordinary use.

Flint Glass is remarkably elastic: it may be spun so thin as to bend nearly double without fracture; by the aid of slight heat, it may be curled into ringlets to represent human hair, or it may be blown so thin as nearly to float in the atmosphere; and it has been woven with silk and other substances by Messrs. Williams and Sowerby's Patent Process, so beautifully as to give the brilliant effects of silver and gold, in colours superior to the precious metals themselves.* Hollow Glass balls are so elastic than if dropped from a height of ten or twelve feet upon a solid polished anvil, they will rebound from half to three-fourths of that height, and generally without fracture, until after the second rebound.

Flint Glass, of not less than the usual density of 3.200, well polished by the lapidary, is considered the nearest approach to the diamond.

Glass is admitted to be one of the most useful and beautiful of materials in ornamental and industrial art. Chemistry and astronomy could scarcely exist without it. The delicacy and accuracy of the chronometer require its aid; while the common green bottle Glass can be manufactured cheap enough for casting conduit pipes, for chemical uses, or the supply of the metropolis with pure water. No chemical test is so delicate