INDEX. 
Mantell, G. Esq. F. L. S. M. G. S., his notice on the Jgiianodon, 
179 — 186. 
Metals, their preservation by electro-chemical means, 328 — mag- 
netic effects manifested by the different, during rotation, 473, &c. 
Mole cricket. See Gryllotalpa. 
Mortality, human, Mr. Gompertz on the law of, 513. 
Mummy. Dr. Granville’s account and dissection of a female 
one, 269 — dimensions of, 278 — dimensions of a male one, 290 — 
perfect preservation of its muscles and other parts, 296. 
N 
Needle, dipping, experiments with, 383. 
Nerves, their existence in the placenta proved, 66 — their influence 
in producing animal heat, 257. 
O 
Observatory at Cambridge, account of the transit at, 418. 
Octahedron in crystallography, theory of its modifications, 106. 
Oil, products obtained from, during its decomposition by heat, 440 
— by compression of oil gas, 441. 
gas, analysis of by sulphuric acid, 462. 
Optical deception. Dr. Roget’s explanation of a curious one, 131. 
Ova, materials of, compared with those of the brain, 436. 
Ovum of the frog, its changes during the formation of the tadpole. 
Peat bogs, remains of the Irish elk found in, 431. 
Photometer, Dr. Ritchie’s account of a new one, 141. 
Placenta, the existence of nerves in, proved, 60. 
PlanaricB, Dr. Johnson’s observations on, 247 — obtain additional 
heads by incision, 247 — Mr. Dalyell’s account of, 247, 8. 
Pond, J. Esq. Astr. Royal, on the annual variations of some of the 
principal fixed stars, 510. 
Powell, the Revd. B., M. A.F. R. S., his experimental enquiry 
into the nature of radiant heat from terrestrial sources, 187. 
Preservation of metals by electro-chemical means, 328. 
Prism, quadrangular, in crystallography, theory of its modifica- 
tions, 102. 
, regular triangular, 119. 
Protecting eflfects of zinc, &c. on copper, how modified by imperfect 
communication, 334, 337. 
