—, examination of columbite, xlix, 228.
Rosin, gas lights from, xxviii, 147.
—, bubbles blown in, ii, 179.
Rosse's great telescope, xlvi, 208; xlix, 221.
Rossie lead mines, xxxvi, 24; xlii, 174.
Rot, dry, G. Gibbs, ii, 114.
—, —, P. Rainey, xxxiv, 169.
—, —, J. T. Plummer, xlii, 197.
Rotary motion, instrument for illustrating, (rotascope) W. R. Johnson, xxi, 265.f
—, multiplier, see under [Electricity.]