4-39 



of 1812, i. 443; observation of the 

 winter solstice of 1812, i. 457; cata- 

 logue of north polar distances of the 

 principal fixed stars, i. 449, 477. 

 ii. 29 ; determination of the north 

 polar distances and proper motion 

 of thirty fixed stars, ii. 29 ; on the 

 parallax of the fixed stars, ii. 65, 

 66, 79, 102; on constructing a cata- 

 logue of fixed stars, ii. 99 ; on the 

 parallax of a. Aquilae, ii. 101 ; let- 

 ter relative to the mural circle at 

 the Royal Observatory, ii. 160; on 

 the changes in the declination of 

 some of the fixed stars, ii. 182, 183, 

 203 ; on the parallax of at, Lyrse, ii. 

 184; on the annual variations of 

 some of the principal fixed stars, ii. 

 251. 



Porpoise, structure of the stomach of, 

 i. 256. 



Porrett (R.) on the constitution of the 

 prussic, of the ferruretted chyazic, 

 and of the sulphuretted chyazic 

 acids, ii. 21. 



Port Bowen : experiments made with 

 an invariable pendulum at, ii. 290 ; 

 on the daily variation and intensity 

 in the dipping and horizontal needles 

 at, ii. 293 ; observations to deter- 

 mine the amount of atmospherical 

 refractions at, ii. 296, 308. 



Portrait, on the apparent direction of 

 eyes in a, ii. 214. 



Potash, discovery of in sea-water by 

 Dr. Wollaston, ii. 112. 



Potassium, an easy mode of procuring, 

 i. 513. 



Powell (Rev. B.), inquiry into the 

 nature of the radiant heating effects 

 from terrestrial sources, ii. 235 ; ex- 

 periments relativa to the passage of 

 radiant heat through glass screens, 

 ii. 280. 



Pressure, its influence in producing 

 double refraction, ii. 7, 389. 



Prevost (P.), Quelques remarques sur 

 la chaleur, et sur 1'action des corps 

 qui 1'interceptent, i. 94. 



Princep (J.) on the measurement of 

 high temperatures, ii. 331 ; meteor- 

 ological journal kept at Benares, ii. 

 340. 



Proteo-Saurus, account of the fossil 

 skeleton of the, ii. m, 128. 



Proteus anguinus, description of, i. 18. 



Proteus, Mexican, on the organs of 

 generation of, ii. 221. 



Prout (Dr. W.) on purpuric acid, ii. 

 100 ; on the changes the egg under- 

 goes during incubation, ii. 175; on 

 the acid and saline matters usually 

 existing in the stomachs of animals, 

 ii. 204 ; on the ultimate composition 

 of simple alimentary substances, ii. 

 321. 



Prussiate of mercury, examination of, 

 ii. 21. 



Prussic acid, the constitution of, ii. 2 1 . 



Pumice, on the formation of, ii. 172. 



Purification of Thames water, spon- 

 taneous, ii. 376. 



Purpuric acid, a compound of ammo- 

 nia with a peculiar acid principle, 

 ii. 100. 



Pus : experiments on, i. 383 ; on its 

 conversion into new flesh, ii. 103. 



Pyrites, magnetical, analysis of, i. 155. 



Pyrometer, Princep's, ii. 331. 



, register, Mr. DanielTs, ii. 



404. 



Pyrometric alloys, on the measurement 

 of high temperatures with, ii. 331. 



Q. 



Quadrupeds, on the intervertebral sub- 

 stance in, i. 329. 



Quagga, singular fact respecting the, 

 ii. 137. 



Quantities, algebraic, capable of geo- 

 metrical representation, ii. 382. 



, imaginary, on, i. 39, 216. 



-, negative, on the objections 



against the geometrical representa- 

 tion of their square roots, ii. 371, 

 382. 



R. 



Raffles (Sir T.), account of the du- 

 gong, ii. 129. 



Rana, account of the urinary organs 

 and urine of two species of, ii. 140. 



Rattlesnake, on the bite of the, i. 354. 



Recoil-engine, ii. 300. 



Red snow, on the fungi which consti- 

 tute the colouring matter of, ii. 128. 



Reeve (Dr. H.), account of cretinism, 

 i. 292. 



Reflecting circle, improved, i. 56. 



Reflexion: prismatic, method of ex- 

 amining refractive and dispersive 



