—, English, viii, 389; x, 194.

—, paramorphine in, xxiv, 374.

—, thebaine in, xxx, 379.

Opossum, remains in the Stonesfield slate, xxvii, 412; xxxvii, 228.

Optics, notice of D. Brewster's Treatise on, xxiv, 389.

Optical amusements, xvi, 398.

— experiment, exhibiting the blood vessels of the eye, xxi, 166.

— deception, instrument for exhibiting a certain, E. S. Snell, xxvii, 310.

— instruments, xix, 390.

— properties of saccharine juice, Biot, xxiv, 379.