382 INDEX. 



Placenta^ observations on the nerve of, 294 -' r 



Platinum, action of, on gaseous mixtures, when finely divided, 



and its application to their analysis, 101-103 

 Plutonian theory of the earth, sketch of, 74-76 

 PoissoHy (M.), on the theory of magnetism, 122-131 

 Po7id, (John, Esq.) method hy, of determining the direction of the 



meridian, 270, 271; on the annual variation of some of the 



principal fixed stars, 278 

 Potato^ cultivation of, considered as to its produce in potash and 



in roots, 331, 332 

 Powell, (Baden) on light and heat from terrestrial sources, 45-61., 



213-216 ; conclusions deducible from his researches into the 



nature of the radiant heating effects from terrestrial sources, 



305, 306 

 Prangos hay plant of Northern India, account of, 1-7 

 Prevost and Royer, (MM.) experiments of, on the digestion of 



ruminating animals, 169-172 

 Prize Questions, proposed by the Royal Academy of Sciences of 



Thoulouse, 165 ; and by the Academy of Sciences at Paris, 369 

 Proceedings of the Royal Society of London, 98-100 

 P sit tacus TieldUy description of, 199, 200 



QuiniUi sulphates of, how prepared, 162, 163 



Rai7ij quantity of, which falls at diflferent heights, 173 

 Regla (Count De), description of coal found on the estates of, 27, 2S 

 Retina, insensibility of, 368 > 



Ritchie (WiWmm), account of a new photometer by, 299-301 

 Rocks, constituents of, 28-32 ; consolidation of, 32-38 ; dif- 

 ferent rocks, and the modes of their consolidation, 38, 43; on 

 the general causes of consolidation, 43, 44 ; analogies among 

 different rocks, and their resemblances to unconsolidated strata, 

 200-208; formation of conglomerate rocks, 208-212; tran^ 

 sitions among rocks, 212, 213; natural transference of rocks 

 and stones, 360-362 

 Rocking -stone, at Savoy, Massachusetts, notice of, 362, 363 

 Roget (Dr.) explanation of an optical deception by, 298, 299 

 Rotation, alteration produced by, on the magnetism of iron 



plates, 263-268 

 Royal Society of London, proceedings of, 98-100, 260-281 ; ana- 

 lysis of its transactions, 100-108, 294-306 

 Ruminating animals, experiments on the digestion of, 169- 172 

 Rumker (Mr. Charles'i catalogue by, of the stars in the comet of 

 Encke, 119, 120 



Sarsaparilla, salifiable base of, discovered, 163 ; its properties, 164 

 Secret Writing ^ method of, 140 



