—, on the geology and mineralogy of Sicily, viii, 201.
—, on the zoological characters of formations, viii, 213.
—, curious effect of solar light, xii, 169, 180.
—, Report on the Geology of Connecticut, notice of, xliv, 187.
—, crescent form of dikes first observed by, xlvi, 205.
Percussion powder, xviii, 156.
Perdicaris, G. A., on the revival of letters in Greece, xxxvi, 192.
Perkins, G. R., interesting properties of numbers, xl, 112.
—, solution of a functional equation, xlii, 69.
—, new method of computing interest, xlvii, 51.