PHILOSOPHICAL 
TRANSACTIONS, 
OF THE 
ROYAL SOCIETY 
OF 
'LONDON. 
FOR THE YEAR MDCCCXVIII. 
P A R? T I. 
PRINTED BY W BULMER AND CO. CLEVELAND-ROW, ST, JAMEs’s; 
AND SOLD BY G. AND W. NICOL, PALL-MALL, BOOKSELLERS TO HIS MAJESTY, 
AND PRINTERS TO THE ROYAL SOCIETY. 
MDCCCXVIII, 
