INDEX. 
page 
Phillips, Richard, Esq. and Michael Faraday, Esq. 
On a new compound of chlorine and carbon, - 392 
Presents, a list of those received by the Royal Society from 
November, 1820, to July, 1821, - - 441 
Proto-chloride of Carbon, a description of it, with experi- 
ments, - - - 64 
Q 
Quagga, a communication of a singular fact relating to 
that animal, - - - 20 
R 
Rana, an account of the urinary organs and urine of two 
species of that genus, - - - - 9.5 
Rete mucosum , on that of the Negro being a defence 
against the scorching effect of the sun’s rays, - - 1 
Rhinoceros, two-horned, from Sumatra, an account of its 
skeleton, - - 270 
Rumker, Charles. Calculations of some observations 
of the solar eclipse on the 7th of September, 1820, - 311 
S 
Sabine, Captain Edward, an account of experiments to 
determine the times of vibration of the pendulum in 
different latitudes, - - - - - 163 
Schehallien experiment, an account of this experiment made 
by Dr. Maskelyne and Dr. Hutton in the years 1774, 
1775, and 1776, - - - - - 2 76 
with that performed by Mr. Cavendish, for ascer- 
taining the mean density of the earth, - - 284 
Sow, particulars of a singular fact relating to the litter of 
one, - - - - 23 
Spherical aberration, developement and application of the 
equations for correcting it, - 254 
Spherical surfaces, general formulae for the focal distances 
and aberrations of any combination of them, - 228 
general theory of their aberrations for 
rays incident in the plane of the axis, - - 237 
Spleen, observations on its structure and uses, - - 38 
Sun's rays, the black rete mucosum of the Negro is a de- 
fence against their scorching effect, 1 
