P Palisa, J., 100. Pallas, 19, 99, 101. Parallax, solar, 61, 62, 63, 101. Parallax, stellar, 150-158, 190. Paris Congresses, 161. Paris Observatory, 78, 118, 171. Perrine, C. D., 81, 108, 194. Perrine’s comet, 136. Perrotin, H., 86, 91, 100, 114. Peck, W., 162. Persei (Nova), 192, 193, 194, 195. Perseid meteors, 122, 141. Perseus, 192, 221. Peters, C. H. F., 100. Peters, C. A. F., 142, 153, 155, 202. Photography, astronomical, 54, 56, 57, 59, 75, 81, 94, 108, 113, 136, 158, 160, 161, 172, 175, 192, 193, 194, 203, 208, 209, 210, 211, 212. Photometry, 176, 177. Piazzi, G., 19, 20, 98, 150. Pickering, E. C., 174, 175, 176, 177, 181, 182, 183, 185, 193, 194, 203, 204, 220, 221. Pickering, W. H., 75, 76, 81, 91, 92, 93, 107, 113, 209. Plana, G., 78, 79. Pleiades, 124, 210, 217. Pogson, N. R., 142, 180. Pole Star, 205. Pollux, 165, 170. Pons, J. L., 127. Pontécoulant, 79. Potsdam Observatory, 46, 173, 176. Pritchard, C., 158, 177. Proctor, R. A., 4, 20, 38, 41, 90, 91, 104, 148, 163, 164, 218, 219, 220, 231. Procyon (α Canis Minoris), 151, 203. Prominences, solar, 52, 53, 55, 64. Puiseux, P., 75. Pulkowa Observatory, 200. Q Quetelet, A., 139. R Radiant points, meteoric, 139, 144, 145, 146. Ranyard, A. C., 106, 146. Red spot on Jupiter, 105, 106. Regulus (α Leonis), 164, 165. Relative parallax, 157. Réseau, Photospherique, 59. Resisting medium, 128. Respighi, L., 55. Reversing layer, 56, 57. Ricco, A., 87, 105. Rigel (β Orionis), 165, 209. Ritchey, G., 194. Roberts, A. W., 181. Roberts, I., 209, 210. Roche, E., 109. Roman College Observatory, 85. Rosse, third Earl of, 141, 156, 207, 208, 218. Rosse, fourth Earl of, 77. Rotation of the Sun, 58, 59; of the planets, 82, 83, 84, 85, 86, 87, 104, 111, 112. Rowland, H. A., 52. Rutherfurd, L. M., 75, 169.