PHILOSOPHICAL 
RANSACTI 
OF THE 
EOYAL SOCIETY 
OF 
LONDON. 
FOR THE YEAR MDCCCLXXXVL 
VOL. 177. 
LONDON: 
PRTNTED BY HARRISON AND SONS, ST. MARTIN’S LANE, W.O., 
printers in Orbinarn to "§ex Utajcstg. 
MDCCCLXXXYII. 
