T O 
Sir Ifaac Newton,- Kt. 
PRESIDENT, 
And to the 
COUNCIL and FELLOWS 
OF THE 
Royal Society of London , 
FOR, 
Improving Natural Knowledge, 
This THIRTY FIRST Volume 
O F 
Philofophical T ranfactions 
la Humbly Dedicated 
B Y 
Their moft Obliged, 
and moft Obedient Servant, 
James Jurin , R S. Seer. 
