[ 445 J 
XL IV. Of the filling of Waves hy means 
of Oil . Extra Sled from f undry Eetters 
between Benjamin, Franklin, LL. D . 
F. R. S. William Brownrigg, M. D. 
F. R. S . and the Reverend Mr . Farifh. 
Extra# of a Letter from Dodtor brownrigg to 
Dr. franklin, dated Ormathwait, January 27, 
J 773* 
Redde, June | j Y the enclofed from an old friend, a 
2 > 1 7 74* worthy clergyman at Carlifle, whofe 
great learning and extenfive knowledge in moft fci- 
ences would have more diftinguifhed him, had he 
been placed in a more confpicuous point of view, 
you will find that he had heard of your experi- 
ment on Derwent Lake, and has thrown together 
what he could collect on that fubjedl ; to which I 
have fubjoined one experiment from the relation of 
another Gentleman. 
Extra# of aLetterfrom the Reverend Mr. farish, 
to Dr. BROWNRIGG. 
I fome time ago met with Mr. Dun, who fur- 
prifed me with an account of an experiment you 
had tried upon the Derwent water, in company with 
Sir 
