—, —, —, method of obtaining, xvi, 295, 297.f

—, palm-glass, cold produced by, xiii, 4.f

—, olefiant gas, on the analysis of, xv, 270.

—, opium, mode of detecting minute quantities of, xii, 290.

—, platina, on the fusion of, xxxiii, 195; xxxv, 328.

—, pneumatic cistern, xiv, 200f; xxxiii, 246.f

—, potassium, improved process for, xxxviii, 338.

—, phosphorus, combustion of, in nitrous oxide, xxxii, 290.f

—, prussic acid, apparatus for the evolution of, xxix, 244.f

—, sassarubrin, a resin, xxxi, 285.