Copper, properties of, i. 4 colour of, in reflected and absorbed light, i. 35, 36 its power of transmitting electricity, i. 90 atomic weight of, compared with that of hydrogen, i. 100 spectra of copper and its compounds, i. 145, 146 Copper, peroxide of, combination forming, i. 104 Coral, structure of the coral polypes, ii. 133, 134 composition of the stony substance of, ii. 137 reef-building corals, ii. 138 red, ii. 125 white, ii. 127 Corallina officinalis, mode of reproduction of, i. 230 structure and development of, i. 240 Corallines, structure and mode of propagation of, i. 240 Corallium Johnstoni, structure and habitat of, ii. 127 Corallium rubrum, structure and mode of reproduction of, ii. 125, 126, 127 coral fishing in the Mediterranean, ii. 126 Corallium secundum, structure of, ii. 127 Cordyceps miliaris, characters of, i. 283, 293 Cordyceps purpurea, the second form of ergot, i. 293 structure of, i. 293 Cordyceps Robertsii, form of, i. 293 Coremium glaucum, production of, i. 287 Corolla of flowering plants, i. 378 Corundum, i. 4 Corynidæ, characters of the family, ii. 90 Cosmarium, structure and development of, i. 194 Cotton, dyes for, i. 125 necessity for mordants for fixing cotton dyes, i. 125 enormous manufacture of cotton in Britain, i. 125 Cowries, shells of, ii. 234, 235 Cow-tree, beverage obtained from the, i. 426 Crabs, structure and mode of reproduction of, ii. 189-197 hermit, structure of, ii. 197 king, fossil, ii. 211 spider, structure of, ii. 211 Creosote, i. 121 its property of preventing the decay of organic matter, i. 121 Cressylic acid, how produced, i. 120, 121 chemical composition of, i. 128 Cristallaria compressa, form of, ii. 28 structure of, ii. 39 Cristata, siliceous skeleton of, ii. 60 Crocus, structure and mode of reproduction of, i. 387, 388 Cruoria pellita, tetraspores of, i. 237 Crustacea, characters of the, ii. 188 fossil crustacea, ii. 211 Crustacea, Decapod. _See_ Decapods Cryptogamia, spores of, i. 177, 178 Cryptonemiaceæ, multitude of forms of, i. 234 structure of, i. 234 Crystal, rock, its transmission of chemical solar rays, i. 65 absorption of invisible rays by, i. 65 change of position of the optical axes of the crystals of, by heat, i. 73