( *•$ ) 
Mr. Gray has Ihown the defeft of his Method, which 
he us’d to recover by grinding and polifhing hisGlafles 
on a Brafs Plane, and fo reduce ’em to Hemifpherules ; 
but how far (hort polifti’d Glafle9 (l fpeak of fmall ones) 
come of thofe which are caft, I leave to any one to 
judge who has feen both. His Water and Quickfilver 
Mifcrofcopes I never faw, fo can fay little to them. 
After what manner Mr. WUfons Glafies are made I 
know not, but fure his greateft Magnifyers are ill plac’d, 
they being funk to fo great a diftance from the Eye, the 
Objedi cannot appear to that Advantage it otherwife 
would 5 if therefore inftead of a hollow Cap he would 
contrive a plain Plate of any Metal for the Reception 
of tfce Glafs, then the Eye and the Objeft might come 
to their due diftance 5 neither ought there to be any 
Calx or Glafs between the Objeft and the Spherule, 
when we ufe the greateft Magnifyers, becaufe if the 
Focus of a Sphere be upon the extremity of its Circum- 
ference, any fmall diftance from that muft fpoil the 
truth of the Objects appearance. 
I cannot fay, that the Glaffes I have made are with- 
out fault, but I think they magnify more than any I 
have yet feen , and were they plac’d to the beft advan- 
tage, they would Magnify much more than they do : 
They are made thus. 
I take a piece of fine Window Glafs, and I rafe it 
with a Diamond into as many lengths as I think need- 
ful, not exceeding an eighth of an Inch in breadth 5 
then holding one of thefe lengths between the Fore- 
Finger and Thumb of each Hand, over a very fine 
Flame, until the Glafs begin to fatten, I draw it out 
till it be as fine as a Hair and break : Then Inuring 
each of the Ends into the pureft part of the Flame, I 
have two Spheres prefentlv, which I can make larger 
or lefs as I pleafe $ if they ftay long in the Flame, 
they'll have fpots, fo I draw ’em out prefently after 
