

tO T BE 
| Right Honourable 
WILLIAM 
Lord Vi-Count BROW NCKER 
PRES DT Db NP: 
Council and Fellows 
ROYAL SOCIETY. 
MY LORD, 
«HE Commands I received from Your Lord- 
foip, and the Royal Society, To profecute 
the Subje treated of in the. Two former Books; 
have produced This which follows. And I 
humbly fubmic the fame to Your Lordthips Judg- 
T > ment : 




































































