Plaster, on the setting of, xvii, 371.

— of Paris, see [Gypsum.]

Plastic clay of the southeast of England, xxxiii, 92.

— — and sand formation of New Jersey, Massachusetts coast, and elsewhere, vii, 34, 214, 244.

Plate electrical machine, R. Hare, vii, 108f; xxxii, 272.f

— — —, viii, 378.

Platinum, size of grains of, xvi, 389.

—, price of, (1833,) xxvi, 210.

—, imitation of, xxii, 383.

—, on the fusion of, R. Hare, ii, 295; xxxiii, 195; xxxv, 328; xxxviii, 155, 163.