Ruhmkorff’s electro-magnetic induction apparatus, i. 32 Russulæ, laticiferous vessels of, i. 263 Rust of wheat, i. 281 Rye, probable cause of the mildew of, i. 297 Rytiphlæa pinastroides, antheridia of, i. 243 Rytiphlæa tinctoria, antheridia of, i. 242 S Saffron, meadow, poisonous alkaloid obtained from, i. 427 Sagartia miniata, structure and habitat of, ii. 132 its deadly weapons, ii. 132, 133 Salpa maxima, structure of, ii. 226, 227 Salpa mucronata, vast shoals of, ii. 228 Salpa zonaria, young of, ii. 227 Salpi, their food, i. 205 Salpidæ, characters of the, ii. 226-228 Salt, change of volume of, by chemical combination, i. 20 partial decomposition of, by diffusion, i. 111 yellow coloured light produced by the combustion of, i. 132 spectrum analysis of, i. 134 Salt: more universally diffused than any other matter, i. 134 spectrum analysis of the rarefied vapour of, i. 141 Sand of the sea-shore, the debris of quartz rocks, i. 17 Sandal wood, amount of radiant heat absorbed by the perfume of, i. 44 Sandhopper, structure of the, ii. 201, 202 Sap milk, composition and formation of, i. 425 Sapindaceæ, or soapworts, fruits of, innocuous, i. 426 Sapphire, i. 4 Sapphirina fulgens, structure and habitat of, ii. 204, 205 Sarcode, structure and functions of, ii. 2 Sarcophycus of the Antarctic Ocean, i. 256 Sarcophycus potatorum, fruit of, i. 256 Sargassum, habitat of the, i. 255 Sargassum bacciferum, structure, fructification, and habitat of, i. 257 Sargassum vulgare, structure, fruit, and habitat of, i. 257 Saturn, the planet, spectrum of, i. 158, 161 Sausages, fatal effects caused by, i. 285 Saw-dust, manufacture of into oxalic acid, i. 116, 117 Scalariæ, tongues of, ii. 239 Scallop, or pecten, eyes of the, ii. 235 Schistocarpi, characters of the group, i. 328 Schistostegei, structure and habitat of, i. 331 Schizæa, structure of, i. 363 Schizæineæ, characters of the, i. 363 sporangia of, i. 343 characters of the group, i. 345 Sclerogen, i. 175 production of, in plants, i. 421 Scolopendrieæ, characters of, i. 351, 352 Scolopendrium, structure and development of the caudex of, i. 340 Scolopendrium vulgare, or Hart’s-tongue fern, structure, fructification, and habitat of, i. 351, 352 Screw pine, roots and habitat of, i. 387 Scutella, spines of the, ii. 180 Scutula, organs of reproduction of, i. 307 Sea-cucumbers, structure and mode of reproduction of, ii. 183 Sea-eggs, or sea-urchins, structure of, ii. 176 _et seq._ Sea-fans, structure of the, ii. 125 Sea-mat, structure of, ii. 218 Sea-nettles, vast shoals of, ii. 100, 101 Sea-pens, structure of, ii. 128, 129-131 Sea-salt, chlorine obtained from, i. 18 Sea-serpent of Celebes, ii. 186 Sea-slugs, structure of, ii. 239, 240 Sea-weeds, former and present uses of, i. 128