i. 35, 36

property of some substances in the transmission of radiant light and heat, i. 36 invisible rays of high heating power existing beyond the red end of the solar spectrum, i. 36 Melloni’s investigation of the laws of radiation and absorption of radiant heat in solid and liquid matter, i. 38 chemical power of the light of the moon and stars, i. 55 and of solar light, i. 56 effect of the opalescence of the atmosphere on the light of the sun, i. 55 probable causes of the blueness of the sky, and the brightness of the tints at sun-rise and sun-set, i. 58 solar spectrum, i. 58 myriads of ethereal waves constituting the seven colours of the, i. 58 fluorescent or degraded light, i. 60 experiment illustrating the change of heat into light, i. 62 absorption of invisible rays, by solids, liquids, and gases, i. 65 causes of earth light, i. 66 polarization of light and heat, i. 68, 69 by reflection and refraction, i. 69 relation of polarization to crystallization, i. 70, 71 M. Gassiot’s experiments on stratified electric light, i. 78 influence of magnetism on the stratified light, i. 78 cause of the stratified discharge, i. 85 effect of varied intensity on electric discharges, i. 86 action of magnetism and electricity on light, i. 90 delicate power of analysis in light, i. 95 Dr. Young’s establishment of the undulatory theory of light, i. 129 Drummond’s light, i. 132 coloured light obtained from the combustion of the salts of different metals, i. 132 effects of light on vegetation, i. 168, 169 effects of light as an exciting cause in the vegetable world, i. 431

Lightning, spectrum of, i. 147

Ligneous tissue, i. 174, 175

Liliaceæ, structure and development of the, i. 388

Limboriei, structure and habitat of the, i. 310

Lime, carbonate of, different modifications assumed by, i. 74 chloride of, properties of, i. 19 oxalate of, formation of, i. 117

Limestones, probable history of the oldest, ii. 52 the nummulitic, ii. 53 the limestone formed by the Eozoön Canadense, ii. 54

Limnoria lignorum, structure of, ii. 203

Limpet, structure, food, and habitat of, ii. 238, 239

Limulus, fossil remains of, ii. 211

Lindsæeæ, characters of, i. 351

Lingbya, structure of, i. 213

Lingula flags, fossil animals composing the, ii. 53

Listera ovata, structure and mode of reproduction of, i. 399

Lithium, i. 3 spectrum analysis of, i. 133 existence of lithium in all three kingdoms of nature, i. 134 spectrum analysis of the rarefied vapour of, i. 142 effect of high temperature, i. 142, 143 chloride of, spectrum of, i. 146

Litmus, or orchil, from what obtained, i. 124, 303

Lituola, structure of the genus, ii. 37

Lituolidæ, characters of the family of, ii. 36, 37

Liver worts. _See_ Hepaticæ

Lobophylla angulosa, structure of, ii. 135, 136

Locomotion of some diatoms, i. 204

Lo-hao, a Chinese green dye, i. 124

Loligo vulgare, or squid, structure of, ii. 245, 246

Lomaria, characters of the genus, i. 357

Lomariopsis, characters of, i. 360

Loxades bursaria, structure of, ii. 72

Loxades bursaria, mode of propagation of, ii. 75

Lucifer, characters of the genus, ii. 200 matches, i. 17

Luminosity of the medusæ in warm seas, ii. 99 of Annelida, ii. 160 of Pyrosomidæ, ii. 226

Lycoperdon giganteum, structure, habitat, and fructification of, i. 267

Lycoperdon, structure and fructification of, i. 267

Lycopodiaceæ, or club mosses, characters of, i. 373 habitat and fructification of, i. 373, 374 uses to which they have been applied, i. 374

Lycopodium, or wolf’s-claw, characters of the genus, i. 374

Lycopodium clavatum, structure and habitat of, i. 374 inflammability of the dried spores of, i. 374

Lycopodium inundatum, structure and habitat of, i. 374

Lygodium articulatum, structure of, i. 363

Lymnæa, or pond snail, distoma of the, ii. 146

M

Macrocystis pyrifera, structure, habitat, and fructification of, i. 250

Macrura, characters of the, ii. 189 fossil remains of, ii. 211

Madder, dyes obtained from, i. 124, 125

Magenta, or aniline red, Dr. Hofmann’s discovery of, i. 122 how produced, i. 122 purple dye produced by mixing it with aniline, i. 123

Magnesium, i. 3, 4 spectrum of, i. 65 spectrum analysis of the rarefied vapour of, i. 142 shown to be one of the metals existing in the sun, i. 151-153 spectrum of the light of a magnesium flame, i. 153, 154 its use in photography, i. 154

Magnetism, i. 30 periodic and secular variations of, i. 30 probably stand in some periodic connection with the solar spots, i. 30, 31 probable cause of terrestrial magnetism, i. 31 difference between magnetic and electric currents, i. 33 relations between the force of magnetism and the atoms of matter, i. 75 all substances either magnetic or diamagnetic, i. 75 proof of the connection between the magnetic forces and crystalline structure, i. 76 conduct of amorphous and isomorphous substances under magnetic influence, i. 76 action of magnets upon matter most powerful in the line of maximum density, i. 76 conditions of the position which crystals take with regard to the magnetic force, i. 76 magnetic changes in the relations and distances between the ultimate atoms of matter, i. 77 effect of magnetism on the stratified appearance of the electric light, i. 78 causes of the polarity of a magnet, according to Ampère, i. 80 action of magnetism on the stratified discharges of electric light, i. 82 illustration of the action of magnetism and electricity on light, i. 90

Maiden’s hair fern, structure and habitat of, i. 359

Malaxis paludosa, or bog malaxis, structure and mode of reproduction of, i. 400

Malic acid, chemical combination forming, i. 97

Manchineel, poison of the, i. 426

Manganese, peroxide of, relative weight of the atoms of oxygen and metal in, i. 99 atomic weight of, compared with that of hydrogen, i. 100 peroxide of, combination forming, i. 104

Manihot, or Cassava, food obtained from the, i. 426

Marasmius Oreades, spawn of, i. 262

Marattia salicina used as food, i. 365

Marattiaceæ, characters of the group, i. 364

Marchantia polymorpha, structure, development, fructification, and habitat of, i. 317-320

Marchantiaceæ, characters of the order, i. 317

Mars, the planet, spectrum of, i. 158, 161

Marsh-gas, i. 118 amount of absorption of radiant heat by, i. 41

Marsilea, characters of the genus, i. 372

Marsileaceæ, or Rhizospermæ, characters of the tribe, i. 371

Matonineæ, characters of the group, i. 344

Matter, molecules of, i. 2 agency of electricity in the chemical composition and decomposition of, i. 32 decomposing and elective power of, i. 35

Mauve, Dr. Hofmann’s discovery of the aniline colour, i. 122 at first made from orchil, i. 124 derived from guano, i. 125

Mediterranean sea, zones of algæ in the, i. 259 foraminifera, the ooze in the bed of the, ii. 51

Medusæ, form and structure of, ii. 91

Medusæ, pulmograde, form and structure of, ii. 91, 92 naked-eyed medusæ, ii. 91-96 mode of reproduction of, ii. 94 armed or stinging medusæ, ii. 99 luminosity of, in warm seas, ii. 99 development of medusa-buds, ii. 96 alternation of generation of hydræ and medusæ, ii. 96 covered-eyed medusæ, ii. 97 parasites of, ii. 99 abundance of species of, ii. 100 food of medusæ, ii. 101

Medusa-buds, development of, ii. 95

Medusiform zooids of hydrozoa, ii. 88, 89

Melanconiei, characters of the group of, i. 281, 282

Melanogaster, the red truffle of Bath, i. 268

Melanospermeæ, characters of, i. 181 marine forests of, i. 244 structure of the, i. 244, _et seq._

Mercury, conditions under which he may be habitable, i. 55

Mercury, its feeble affinity for iron, i. 98

Meridion circulare, structure and development of, i. 200, 201

Merulius lacrymans, the cause of dry rot in wood, i. 266

Mesocarpus, reproduction of, i. 217

Mesogloias, structure of, i. 245

Metals and their properties, i. 3 alkaline metals, i. 3 of alkaline earths, i. 3 from non-alkaline earths, i. 4 avidity of some of them for oxygen, i. 4 metals whose oxides are not reducible by heat, i. 4 diatomic metals, i. 4 triatomic metals, i. 5 conduction of heat and radiation, i. 5 vaporization, i. 5 spectra of volatilized metals, i. 64 coloured light obtained from the combustion of the salts of different metals, i. 132 spectrum of, not always the same, i. 145 number of the metals of which the spectra has been determined i. 147 metals shown to exist in the sun, i. 151-153 and not to exist in it, i. 154 metals contained in every plant, i. 414

Meteorites probably not of solar origin, i. 153

Mica, opacity of, to the invisible rays, i. 65

Mignonette, weight of the perfume of, i. 45

Mildew of the vine, hop, &c., i. 295 the black mildews of the Azores and Ceylon, i. 297

Miliola, structure and habitat of, ii. 30 abundance of, in the seas of the Eocene period, ii. 31

Miliolidæ, characters of the order, ii. 30

Milk sap of plants, i. 425 vessels of plants, i. 417

Milleporæ complanata or palmipora, structure of, ii. 141

Mimosa pudica, irritability of the tissues of, i. 432

Mind and matter connection between, ii. 5

Molecules of matter, i. 2 cohesion of, i. 25 unit of mechanical force, i. 26 causes of the ethereal undulating motions of, i. 34, 35 _See_ Atoms

Mollusca, structure, habitat, and mode of reproduction of, ii. 229, _et seq._ shells of the, ii. 232 naked, ii. 240 winged, ii. 240

Monas corpusculus, extreme minuteness of, ii. 63, 67 and of its ova, ii. 67

Monocotyledonous, or endogenous plants, structure, growth, and reproduction of, i. 383 seeds of this class, i. 383 stems, or axes, i. 384 remarkable plants belonging to the monocotyledons, i. 387

Monostoma, or one-mouthed medusæ, structure and mode of reproduction of, ii. 97

Monormia, habitat and structure of, i. 212

Moon, interception of the heat radiated by the full, by the earth’s atmosphere, i. 55 its effect on the higher regions of the atmosphere, i. 55 chemical power of the moon’s light, i. 55

Moonstone, or adularia, fluorescent property of, i. 66

Moonwort, structure, and habitat of, i. 366

Morchella esculenta, the morel, i. 291 katsup made from, i. 292

Mordants for fixing dyes in cotton cloth, i. 125

Morphine, the probable narcotic principle of opium, i. 427

Mother-of-pearl, composition of, ii. 234

Motion, effect of, on molecular arrangement, i. 91

Moulds, fungus, on various substances, i. 285

Mucedines, structure of the, i. 283 the origin of all fermentation, i. 289

Mucorini, or moulds, structures of the, i. 296 habitat of the, i. 296, 297

Muriatic acid, formation of, i. 20 action of, upon ammonia, i. 120

Musci, or Mosses, structure and mode of reproduction of, i. 3 antheridia of, i. 324 sporangia of, i. 325 gemmæ or buds, i. 327 leaves of, i. 330 aquatic mosses, i. 331 peat, i. 333 uses of mosses, i. 334

Muscle, structure and functions of, ii. 2 functions of the muscles, ii. 5 electric currents formed in the muscles, ii. 7 muscular respiration, ii. 8

Mushrooms, i. 261 mycelium, or spawn, i. 262

Musk, power of absorption of radiant heat by the perfume of, i. 45

Mussel, structure of the gills of the common, ii. 230

Mycelium or mushroom spawn, i. 261, 262

Mysis, or opossum shrimps, structure of, ii. 199

Myxogastres, structure, habitat, and reproduction of, i. 269, 270 their Amœba-like motions, i. 270

N

Naïs, structure and habitat of the, ii. 152, 153

Naphtha, manufacture of, i. 120 uses to which it is applied, i. 120 sources of, in various parts of the world, i. 126 naphtha procured by the distillation of petroleum, i. 127

Naphthalin, production of, i. 127

Narcotics, exciting, known to almost all people, however savage, i. 427

Navicula, structure of, i. 198

Naviculæ, spontaneous locomotion of, i. 202

Nebulæ, spectra of various, i. 158-160, 163 constitution of the, i. 163 probable existence of primordial nebulous matter according to the theories of Sir W. Herschel and La Place, i. 164

Nectria, characters of the genus, i. 295

Nectria Peziza, structure of, i. 295

Nematoid entozoa, structure and mode of reproduction of, ii. 146

Nemertes gigas, or great band worm, nervous system of, ii. 158

Neotteæ, characters of the British tribe of, i. 397, 398

Neottia Nidus-avis, structure and mode of reproduction of, i. 400

Nephrolepis tuberosa, characters and habitat of, i. 348

Nereis, structure of, ii. 157

Nereis diversicolor, mode of reproduction of, ii. 160

Nereocystis Lutkeana, structure and habitat of, i. 249

Nerve-force of animals, ii. 4, 6 chemical powers generated by, ii. 6

Nerves of animals, structure and functions of, ii. 5 electric currents in the, ii. 7 structure and functions of the brain and spinal cord, ii. 8 the nervous systems of the higher and lower animals, ii. 9-11

Nervous system of animals, ii. 5

Nickel, i. 4, 5 crystals of, formed artificially by electricity, i. 74 effect of heat on the magnetism of, i. 77 atomic weight of, compared with that of hydrogen, i. 100

Nidulariacei, characters of the order of, i. 272, 273 structure and mode of reproduction of, i. 273 habitat of, i. 273

Nitella flexilis, structure and mode of reproduction of, i. 312

Nitophyllum, structure and fronds of, i. 238, 239

Nitric acid, combination forming, i. 95

Nitrogen gas, i. 12 combination of nitrogen with chlorine, i. 20 absorptive power of, i. 39, 41 fulminates compounds of, i. 92 number of combinations of, with oxygen, i. 95 atomic weight of, compared with that of hydrogen, i. 100 one of the illuminants in coal gas, i. 118 spectrum analysis of, i. 140, 145 in high temperature, i. 144 binoxide of, combination forming, i. 95 chloride of, catalysis of, i. 91 iodide of, catalysis of, i. 91 protoxide of, or laughing gas, combination forming, i. 95

Nitrous oxide, absorption of, radiant heat by, i. 41, 43 combination forming, i. 95

Noctiluca miliaris, structure and mode of propagation of, ii. 73, 74

Noctiluci, their food, i. 205

Nodosaria, characters of the genus, ii. 39

Nodosaria rugosa, shell of, ii. 28 structure of, ii. 39

Nodosaria spinicosta, form of, ii. 28 structure of, ii. 39

Nostoc commune, wide distribution of, i. 212

Nostochineæ, structure and habitat of, i. 211 reproduction of, i. 212 wide distribution of, i. 212

Nullipores, structure and habitat of, i. 142

Nummulites, structure of the, ii. 44-46 circumstances favouring their existence in the Tertiary period, ii. 53

O

Ocean, force exerted in the creation of the, i. 31

Octoblepharum albidum, leaves of, i. 330

Octopods, structure of, ii. 245

Octopus vulgaris, or poulpe, structure of, ii. 245-247

Odonthalia, structure of, i. 242

Œdogonium capillare, reproduction of, i. 216

Oïdium, structure and habitat of, i. 290

Oïdium Tuckeri, or vine mildew, fungus producing, i. 295

Oils, dead, manufacture of, i. 120 essential, chemical combinations forming, i. 97 vegetable, i. 422 formation of fixed and essential, artificially, i. 424

Oleandra, characters of the genus, i. 347

Oleandra neriiformis, structure of, i. 347

Olefiant gas, absorptive power of, i. 39, 40, 41 amount of absorptive power, i. 41 great absorption of, i. 47 formation of, i. 97 amount of carbon in, i. 105 one of the illuminants in coal gas, i. 118 chemical composition of, i. 128

Olefiant oil, i. 104

Olive oil, i. 422

Onion, structure and mode of reproduction of, i. 388

Oniscus, common wood-louse or slater, structure of the, ii. 202

Onoclea, characters of the genus, i. 348

Onoclea sensibilis, characters and habitat of, i. 348

Oolina claxata, shell of, ii. 48

Opacity in liquids and solids synonymous with accord, i. 37 causes of opacity, i. 37

Operculina, structure of, ii. 38, 46 an instance of an individual combined with a common life, ii. 38.

Ophioglossaceæ, characters of the group, i. 365

Ophioglossum, characters of the genus, i. 365

Ophioglossum vulgatum, structure and habitat of, i. 365

Ophionyx, structure of, ii. 173

Ophiuridæ, or snake stars, structure of, ii. 172, 173 power of reproducing rays, ii. 173

Ophrys apifera, or bee ophrys, structure and mode of reproduction of,