Pisolite in Massachusetts, ii, 238.
Pisolitic balls, xliv, 283.f
Piston, Cooper's rotative, xvi, 313.f
Pittsburg, Pennsylvania, account of, S. P. Hildreth, xxix, 68, 79.
Pixii, rotating magnetic machine, xxiv, 144, 146f, 196.
Plague in Constantinople, remarks on, xxxiv, 32.
Planes, inclined, in the construction of rail roads, J. Thomson, xxiii, 107.
Planera, or Siberian elm, notice of, xx, 377.
Planet, supposed new, beyond Herschel, Cacciatore, xxxi, 158.
— Jupiter and his satellites, Struve, xiii, 173.