— —, geological section from, to Troy, C. Dewey, ii, 246.
— system, remarks on, D. D. Owen, xlvi, 145.
— —, remarks on, H. D. Rogers, xlvii, 150.
— —, work on, by E. Emmons, noticed, xlviii, 394.
Tagua-nut, or vegetable ivory, xlix, 400.
Tails of comets, x, 395; xxxi, 142, 325; xxxiii, 5, 11; xxxviii, 35; xl, 59; xlvi, 108.f
Talbot, H. F., photogenic drawings, xxxvii, 169; xxxviii, 97.
—, improvement in the telescope, xliv, 166.
Talc from Chamouni, analysis of, xlvii, 216.
— in Connecticut, x, 14.