t x0 7 3 
much as the fubjed has never been fully treated by 
any author, I fhall endeavour, as foon as may be, to 
draw up a more particular explanation of the aberra- 
tions of light by refradion j but fhall add no more 
at prefent, only beg leave to take this opportunity of 
fubfcribing myfelf 
Vine-Court, Feb. 2i, 
Your much obliged and 
molt humble fervant, 
John Dollond 
* 753 - 
O 2 
XVL 
