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IV. A Letter from Dr. Archibald Adams to Dr. 
Hans Sloane, S . Seer, concerning the Manner 
of making Micro/ copes, &c. 
Norwich , Auguft u. 1709. 
SIR , 
P Urfuant to what I wrote fome time ago concern- 
ing Microfcopes, I think that all the Microfcopes 
which preceded Mr. Leeuwenhoek s, are fo much out- 
done by his, that it will be proper for me only to take 
Notice of thefe and the reft of later Invention, not de- 
fining to leffen their Ufefulnefs, but only to add a few 
Thoughts which may be of Service. 
I had not an opportunity of examining Mr Leeumtr 
hoek s Glaffes particularly, which is a Favour he allows 
to none 5 therefore I am not capable at this diftance to 
deferibe either their Make or Ufe, any further than that 
to me they appear’d to be Spherules lodg’d between 
two Plates of Gold or Brafs, in a hole whofe Diameter 
might not be bigger than that of a fmall Pins head, and 
the Obje&s I faw through them were pretty and divert- 
ing 5 but ftill their Make and Truth are unknown. 
Mr. Butterfield is very Curious in melting his Glafs, 
but 1 fuppofe unfuccefsful in carting his Spheres 5 for 
befides that a fufficient quantity of beaten Glafs cannot 
flick to the moiftned Point of a fine Needle * fo neither 
can it run equally, hold the Needle how you will, nor 
the Globule when run flick to the Needle, but muft un- 
avoidably drop 3 and wherefoever it happens to fall, it 
muft in that almoft liquid State receive Impreffions fuf- 
ficient to fpoil the Figure of a Sphere. 
Mr. 
