C5+] 
VII. An Account of an Improvement made 
by Mr, Peter Dollond in his New 7^- 
If copes : In a Letter to James Short, 
M, A, F. R, S, with a Letter of Mr, 
Short’s to the Rev, Thomas Birch, D, D, 
Secret, R, S, 
Dear Sir, 
Surry-Street, Feb. 7, 1765. 
I H AV E fent you, inclofed, a letter which I re- 
ceived this morning from Mr. Dollond, concern- 
ing an improvement which he has made in Iiis new 
telcfcopes. He, fome months ago, fent me a tele- 
fcope, in this new way, of 3 i. feet focal length, with 
an aperture of 3 ^ inches ; I examined it, and I ap- 
proved of itj I have tried it with a magnifying power 
of 150 times, and I found the image diftind, bright, 
and free from colours. 
You may, if you pleafe, lay Mr. Dollond*s letter 
before the Royal Society. 
I am. 
Dear Sir, 
Your moft obedient, 
and humble fervant, 
James Short. 
