INDEX. 
P 
page 
Pearson, George, M. D. On expectorated matter, 
Phosphorus , decomposition of, 
Plumbago , experiments on, - 
Potassium , its action on ammonia, - - 
of its solution in hydrogen, - 
of its alloy with sodium, - - 
of its action on boracic acid, 
on fluoric acid, 
• on muriatic acid, 
on sulphuretted hydrogen, 
Presents received by the Royal Society from November 1 808 
to June 1 809, - 
Prism , how concerned in the formation of the blue bow and 
streaks, ------ 
Pus , on its composition, 
Pyrophorus, Homberg s, probably formed by the decomposi- 
tion of potash, .... 
5 
67 
70 
40 
57 
59 
77 
86 
91 
63 
371 
280 
384 
100 
Q. 
Quinquesection , methods of performing it described, - 29 5 
R 
Ramsden. His method of dividing noticed, - - 112 
Rennell, James, Esq,, on the effects of westerly winds in 
raising the level of the British channel - 400 
Respiration, on - - - - - 404 
Rings , concentric, continuation of experiments for investigating 
the cause of them, and of other appearances of a similar 
nature, - - - - - -2 59 
coloured, their production, - - 264 
Newtonian coloured, on the primary cause 
of their origin, - 299 
Roots, on their origin and formation, - - 169 
their functions, - - - - 1 7 5 
S . 
Saliva , on its composition, - - - 380 
Secretions , animal, hints on the subject, - - 385 
their probable cause, - - ib. 
Serum of the blood, action of voltaic electricity on it, - 389 
Sewell, Mr. Wm. A letter on a canal in the medulla spi- 
nalis of some quadrupeds, - - - - 146 
