430 



egg undergoes during incubation in 

 the common fowl, ii. 172; on the 

 placenta, ii. 176; new classification 

 of animals, founded upon the struc- 

 ture of the placenta, ii. 176; on the 

 difference of structure between the 

 human membrana tympani and that 

 of the elephant, ii. 181 ; on the 

 double organs of generation of the 

 lamprey, conger eel, common eel, 

 barnacle, and earth-worm, ii. 188; 

 on the internal structure of the hu- 

 man brain, ii. 203 ; some curious 

 facts respecting the walrus and seal, 

 ii. 213; account of the organs of 

 generation of the Mexican Proteus, 

 ii. 221 ; on the existence of nerves 

 in the placenta, ii. 226 ; on the 

 changes the ovum of the frog under- 

 goes during the formation of the 

 tadpole, ii. 227 ; on the influence of 

 nerves and ganglions in producing 

 animal heat, ii. 238, 259 ; on the 

 materials of the brain and of the ova 

 of animals, ii. 247 ; on the structure 

 of a muscular fibre from which is 

 derived its elongation and contrac- 

 tion, ii. 259 ; on the coagulation by 

 heat of the fluid blood in an aneu- 

 rismal tumour, ii. 268 ; on the pro- 

 duction and formation of pearls, ii. 

 278 ; on the mode of propagation of 

 the oyster and fresh- water mus- 

 cle, ii. 301 ; on the structure of the 

 cells of the human lungs, and the 

 office they perform in respiration, 

 ii. 303 ; on the effects produced upon 

 the air cells of the lungs when the 

 pulmonary circulation is too much 

 increased, ii. 321 ; on the stomach 

 of the zariffa, ii. 389. 



Homer (H. G.), new method of solv- 

 ing numerical equations, ii. 117. 



Horsburgh (J.), observations on a diur- 

 nal variation of the barometer be- 

 tween the tropics, i. 185; remarks 

 on icebergs met with in the southern 

 hemisphere, ii. 392. 



Howard (E.) on a new fulminating 

 mercury, i. 18; on stony and metal- 

 line substances, said to have fallen 

 on the earth, i. 75 ; on various kinds 

 of native iron, i. 79. 



Howard (L.) on the extraordinary de- 

 pression of the barometer, Dec. 1 82 1 , 

 ii. 163. 



Hultne (Dr. N.) on light which is 

 spontaneously emitted, i. 11, 60. 



Human skeleton, fossil, from Guada- 

 loupe, i. 487. 



Humphreys (Col. D.) on a new variety 

 in the breeds of sheep, i. 451. 



Hutton (Dr. C.) on the mean density 

 of the earth, ii. 148. 



Hydrargillite, a new mineral, i. 183. 



Hydraulic investigations for ascertain- 

 ing the motion of the blood, i. 298, 

 314. 



Hydrocarbon, ii. 272. 



Hydrogen, nature of, i. 351, 353. 



Hydrogen and charcoal, on the aeri- 

 form compounds of, ii. 143. 



Hydrogen gas, vibrations of a pendu- 

 lum in, ii. 368. 



Hygrometer, improved, ii. 258. 



Hyperbola, on the rectification of the, 

 i. 393. 



Hyperoxymuriates, on the action of 

 acids on, ii. 20. 



Hypophosphorous acid of M. Dulong, 

 Sir H. Davy on, ii. 96. 



I. 



Ibis, account of two mummies of the, 



i. 201. 

 Ice : found in the bottoms <of rivers, 



ii. 46 ; on the elasticity of, ii. 276. 

 Icebergs of the southern hemisphere, 



remarks on, ii. 392. 

 Iceland crystal, oblique refraction of, 



i. 92. 

 Igneous and aqueous formations, on 



the analogy between, i. 153. 

 Iguanodon, a newly discovered fossil 



reptile, ii. 234. 

 Illuminating powers of olefiant coal 



and oil gases, ii. 120. 

 Illumination of light-houses, on, ii. 



411. 



Imaginary quantities, on, i. 39, 216. 

 Imperial standard yard, ii. 257, 409. 

 Incubation, on the change the egg un- 

 dergoes during, ii. 172, 175. 

 Infinite series, new methods of finding 



the sums of a variety of, ii. 115. 

 Insects, on the brain of, ii. 203 ; sex 



not given to the eggs of at any very 



early period of their growth, ii 347. 

 Intestinal concretions, ii. 156. 

 Intestines, small, of birds, i. 401. 

 lodates, ii. 20. 



