into a pot of melted Glass. This agitating iron had a long handle with a flat ring, or hand-guard, which rested while in use upon the shoulders of the pot: it was then introduced into the fire-clay cylinder, or sheath, and when the metal was at its utmost intensity of fusion, the mixing began, and continues for many hours, until the operator presumed the striæ were dissipated; then, by gradually reducing the heat of the furnace, the Glass became too stiff for agitation, and the pot, and its contents were annealed in the furnace. Crown Glass will not allow of so many hours' intense fusion and agitation as Flint Glass, owing to its liability to devitrify. M. Bontemps does not assert that he always succeeded in the stirring system, for Flint Glass. He sometimes found hard masses of small cords, as it were, felted together: these he thought were caused by the chemical action of the Glass upon the fire-clay cylinder and pot; but they spread in the operation of cooling. His plan of cleaving pieces from the blocks of Glass, and softening the disks in moulds, was similar to that of Mr. Frauenhofer. He suggested an iron agitator cased in platinum as a practical improvement, which the author of this work thinks is chemically objectionable. He also recommended that an entire pot of flint metal, fused upon the agitation system, should be emptied upon an iron table, and cast the same as Plate Glass. Mr. Dollond has used this kind of French Glass with partial success, although it has not generally been sufficiently annealed. M. Bontemps's proportions are as follow: