PHILOSOPHICA L 
TRANSACTIONS, 
OF THE 
ROYAL SOCIETY 
O F 
' * 
LONDON. 
VOL. LXXI. For the Year 1781. 
PART I. 
LONDON, 
SOLD BY LOCKYER DAVIS, AND PETER ELMSLY, 
PRINTERS TO THE ROYAL SOCIETY. 
MDCCLXXXI 
