406 INDEX. 



netism, 126-130. Account of his experiments with the magne- 

 tic needle, 342, 343 



Oils, new process for extracting elainefrom, 109 



Olbers, (Dr.), catalogue of the orbits of all the comets hitherto 

 computed, 149-154, 349-356 



Ovum, human, notice of Sir Everard Home's discovery of, 321- 

 323 



Painting on pottery, experiments on, 156 



Pajot des Charmes (M. C), notice of the new coloured test papers 

 invented by, 380 



Parhelia seen at the Cape of Good Hope, account of, 365, 366 



Partington (Miles, esq."), case of dumbness cured by, by means of 

 electricity, 187-189 ' 



Payne (M.), new vegetable principle discovered by, 387 



Peclet (M.), new process by, for extracting elainefrom oils, 109 



Penn (Granville), supplement to the comparative estimate of the 

 mineral and mosaical genealogies, analysis of, with remarks, 309- 

 321 



Perkins's engine, change of fat in, by water, heat, and pressure, 

 172, 173 



Phillips (Mr.), experiments of, to determine the certainty of che- 

 mical analysis, 378. On the composition of the muriates of 

 Baryta, Strontia, and Lime, 384 



Phocenic acid, comparative examination of, 112, 113 



Pigment (Green), directions for preparing, 385, 386 



Plants, experiments on the circulation of the sap in, 388-391. On 

 their epidermis, 391. Mode of union in their vegetable struc- 

 ture, 392. On their air-vessels, 392, 393 



Plate-Glass, purple tint of, affected by light, 164 



Platinum, chromium detected in the ore of, 166. Hydriodic acid, 

 a test for, in solution, ibid. Extraordinary experiment on the 

 ignition of, by a jet of hydrogen, 179. And its action on mix- 

 tures of oxvgen, hydrogen, and other gases, 375, 376-378 



Plumbago, fusion of, 157, 158. Notice of artificial plumbago, 

 162 



Poland, notice of organic remains in, 179 



Pollen of the Portluca Oleracea, microscopical observations on, 

 390, 391 



Pond (John, esq.), address to, on his receiving the Copley medal, 

 298, 299. Observations of, on the changes which have taken 

 place in the declination of some of the principal fixed stars, 328, 

 329. And on the parallax of a lyre, 329, 330 



Population of Great Britain, remarks on the changes of, as divided 

 into the classes of agriculturists, manufactures, and non-produc- 

 tive labourers, 203-210 



Prevost (Dr.), and Dumas (M.), examination by, of the blood, 



