PHILOSOPHICAL 
TRANSACTIONS 
OF THE 
R O Y A L S 0 C I E T Y 
OF 
LONDON. 
FOE THE YEAE MDCCCLXXXL 
VOL. 172.—PART HI. 
LONDON: 
PRINTED BY HARRISON AND SONS, ST. MARTIN’S LANE, W.O., 
B rhtfa'S iit Orbtnmi’g to- pM gftajestg. 
MDCCCLXXXII. 
