292 INDEX. 



Matter : agency of electricity in the chemical composition and decompo- 

 sition 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 algae in the, i. 259 



foraminifera, the ooze in the bed of the, ii. 51 

 Medusae, form and structure of, ii. 91 

 Medusae, pulmograde, form and structure of, ii. 91, 92 



naked-eyed medusae, ii. 91-96 



mode of reproduction of, ii. 94 



armed or stinging medusae, ii. 99 



luminosity of, in warm seas, ii. 99 



development of medusa-buds, ii. 96 



alternation of generation of hydrae and medusae, ii. 96 



covered-eyed medusae, ii. 97 



parasites of, ii. 99 



abundance of species of, ii. 100 



food of medusae, 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 

 Melanospermeae, 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, L 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 



