C 230 ] ; 
giving you this trouble, and deiire it may be Iayed 
afide j but, if it be thought worthy communicating 
to the Royal Society, I will be ready, in a very 
fimple and eafy manner, to demonftrate the truth of 
the above difcovery. I do not fee any ufe of this dif- 
covery at prefent, more than an amufing fpeculation; 
tho’ perhaps, when it is reconfidered by perfons fu- 
perior to me in penetrating into the fecrets of op- 
tics, fome real ufe may be made of it. 
I am Sir, with great 
June 15, 1763. 
refpedl, your very 
humble fervant 
George Edwards. 
XXXVI. An 
