Palæolithic man, 212; relics, 213; life, 214, 216
_Penicillium glaucum_, figured, 61; growth of, 63
Penumbra of an eclipse, 23; of sun-spots, 140
Photographic camera, 3, 47; attached to telescope, 121
Photographs of the moon, 13, 19; of galloping horse, 48; of the stars, 49, 161; of the sun, 121
Philadelphia, electric shocks at during sun-storm, 143
Plains of the moon, 10; nature of the, 12
Plants, colourless, single-celled, 65; single-celled green, 78; two kinds of in lichens, 80; with flint skeletons, 185
Plato, a lunar crater, 10, 24; figured, 20
_Pleurococcus_, a single-celled plant, 78
_Polysiphonia_, a red seaweed, 175; fruit of, 177
_Polytrichum commune_, a hair moss, 88; its urns protected by a lid, 91
Proctor, his star atlas, 146; on drifting of Charles's Wain, 159
Prominence-spectrum and sun-spectrum compared, 134
Prominences, red, of the sun, 125; seen in full daylight, 131-133; shape of, 135
Rain-shower during volcanic eruption, 107
Reservoirs of molten rock underground, 101
Retina of the eye, 31; image of object on the, 33
Richmond, Virginia, infusorial earth of, 186
Rigel, a star in Orion, 149; a coloured double star, 168
Roberts, Mr. I., his photograph of Orion's nebula, 152; and of nebula of the Pleiades, 153; and of nebula of Andromeda, 164
Rosse, Lord, his telescope, 46; on Orion's nebula, 150; stars visible in his telescope, 160
Rue, De la, his photograph of the moon, 13
Seaweeds, a group of, 175; fruits of, 177
Secchi, Father, on depth of a sun-spot, 139
_Sertularia tenella_, structure of, 180; _cupressina_, 181
Sertularian and coralline, resemblance of, 179
Shipley, Mr., saw volcanic island formed, 103
Sirius, 146; a bluish white sun, 166; irregularities of caused by a companion, 169
Sky, light readings in the, 53, 127, 151, 168
Spectroscope, 3; Kirchhoff's, 51; gases revealed by the, 52; direct vision, 127; sifting light, 126; attached to telescope, 132
Sphacelaria, a brown-green seaweed, 175; fruit of, 177
Sphagnum or bog moss, 77, 93; structure of leaves of, 93
Spores of moulds, 63; of mushroom, 70; of lichens, 83; of mosses, 91
Star, occultation of, by the moon, 24; a double-binary, 166; a dark, travelling round Sirius, 169
Stars, light from the, 40, 42; visible in the country, 145; apparent motion of the, 146; maps of, 148, 156; of milky way, 149; binary, 154; real motion of, 159; drifting, 159; number of known and estimated, 161; colours of, 166; double coloured, 167; cause of colour in, 168; are they centres of solar systems? 170