INDEX 
TO THE 
PHILOSOPHICAL TRANSACTIONS 
FOR THE YEAR 1821. 
A page 
Ammonia found in the products of papyri, arising probably 
from the decomposed glue used in the manufacture of 
the ink, - - 198 
B 
Bakerian Lecture , on the best kind of steel and form for a 
compass needle, by Captain Henry Kater, - 104 
Barlow, Peter, Esq. On the effects produced in the 
rates of chronometers by the proximity of masses of 
iron, - - - - - 361 
Bell, Charles, Esq. On the nerves, giving an account 
of some experiments on their structure and functions, 
which lead to a new arrangement of the system, - 398 
Brain and Nerves , observations showing that the materials 
of which they are composed exist in the blood, - 25 
Brassa Island , experiments to determine the times of vi- 
bration of the pendulum there, - 165 
Brinkley, Reverend John, D. D. An account of obser- 
vations made with the eight feet astronomical circle, at 
the Observatory of Trinity College, Dublin, since the 
beginning of the year 1818, for investigating the effects 
of parallax and aberration on the planes of certain fixed 
stars ; also the comparison of these with the former ob- 
servations for determining the effects of lunar nutation, 327 
MDCCCXXI. 3 M 
