Pearl ashes, method of manufacturing, G. A. Rogers, viii, 304.
Pearls and pearl fishery, xxxii, 56, 68.
—, in fluviatile shells, xxv, 257.
Pearson's Domestic Telegraph, iv, 314.f
Peat, on the use and mode of formation of, E. North, xi, 67.
—, on the origin, preparation and uses of, from a memoir by Ribaucourt, xv, 250.
—, gas light from, xxx, 189.
—, instance of bituminization of, in Maine, C. T. Jackson, xxxiv, 73.
—, in Massachusetts, xxii, 38.
—, in New York, i, 139; v, 8; xxxvi, 16.