INDEX. 



551 



tions of the positive and negative 

 optic axes of crystals, 450. 



Polarization, on circular magnetic, 

 481. 



Poselger (M.) on the impurity of com- 

 mercial bromine, 399. 



Post-office regulations, notice respect- 

 ing, 158. 



Potter (Prof.) on the discovery of the 

 chilling process in the casting of 

 the specula for reflecting telescopes, 

 246. 



Powell (Prof.) on irradiation, 459. 



Pratt (T. H.) on an analytical proof 

 of the parallelogram of forces, 201. 



Pringle (W.) on the continuance of a 

 solar spot, 48. 



Protogine of the Alps, on the, 233. 



Provostaye (M. F. de la) on the re- 

 flexions of different kinds of heat 

 by metals, 471. 



Quaternions, a new system of imagi- 

 naries in algebra, on, 294, 340, 425. 



Quetelet's (M. A.) Letters to H.R.H. 

 the Grand Duke of Saxe Coburg and 

 Gotha, on the Theory of Probabili- 

 ties, notice of, 297. 



Rain, on the depth of, which falls at 

 different altitudes in Lancashire, 

 Cheshire, &c., 308. 



Reade (Rev. Mr.) on the transit of 

 Mercury, 143. 



Rebmann (Rev. Mr.) on a snowy 

 mountain in Eastern Africa, 388. 



Regnault (J.) on some phsenomena of 

 binocular vision, 269. 



Reich (Prof.) on the repulsive action 

 of the pole of a magnet upon non- 

 magnetic bodies, 127. 



Reymond (M. Du Bois) on the deflec- 

 tion of the magnetic needle by the 

 act of volition, 543. 



Richardson (J.) on Mr. Struve's mine 

 ventilator, 388. 



Rive (A. de la) on the diurnal varia- 

 tions of the magnet needle, and on 

 aurorae boreales, 286. 



Rivot (M.) on California gold, 394. 



Rose (H.) on the existence of mercury 

 in the Tyrol, 318 ; on the isomeric 

 modifications of phosphoric acid, 

 321. 



Royal Astronomical Society, proceed- 

 ings of the, 63, 138, 216, 459, 532 ; 

 anniversaryaddi'ess of the President, 

 218. 



Royal Society, proceedings of the, 73, 

 299, 463, 529. 



Sabine (Lieut.-Col.) on the causes 

 which produce the diurnal variation 

 of the magnetic declination, 466. 



Saint-Evre (M. E.) on chloroniceic 

 acid, and the chloroniceates, 474. 



Schroetter (M.) on a new modification 

 of phosphorus, 78. 



Senarmont (M.) on the artificial pro- 

 duction of several minerals, 545. 



Shea butter, on the composition of, 

 350. 



Shooting star, on the calculation of 

 the distance of a, 179. 



Smith (A.) on the calculation of the 

 distance of a shooting star, 179. 



Smith (Dr. R. A.) on a mode of ren- 

 dering substances incombustible, 

 116. 



Smith (Mr. R.) on the aurora borealis 

 which occurred on the 1 7th of No- 

 vember 1848, 305. 



Soda manufacture, on the products of 

 the, 15. 



Solar halos, on some remarkable, 410. 



Solar spot, on the duration of a, 48. 



Sound, on some points in the re- 

 ceived theory of, 52, 88, 136, 203, 

 348, 401, 501 ; on the theoretical 

 value of the velocity of, 284; on 

 the determination of the velocity of, 

 on the principles of hydrodynamics. 



Sounds, multiple, of bodies, on the, 



415. 

 Spectrum, on the theory of certain 



bands seen in the, 309. 

 Specula, description of a machine for 



polishing, 143 ; on the discovery of 



the chilling process in the casting 



Squares, on a theorem respecting the 

 products of, 113. 



Steam, tables of the pressure of, at 

 different temperatures, 8; on the 

 magnetism of, 502. 



Stenhouse (J.) on the proximate prin- 

 ciples of some lichens, 463. 



Stevenson (W. F.) on the peculiar 

 cooling effects of hydrogen and its 

 compounds in cases of voltaic igni- 

 tion, 304. 



Stokes (G. G.) on some points in the 

 received theory of sound, 52, 203, 

 348, 501 ; on the formation of the 



