IV. ExtraB of fome Letters fent to Sir G. H. re^ 
luting to fome Microffocal Ohferyations. Commmii-' 
cated by Sir C. H. to the Tuhlifher. 
Aug. II. 1702. 
Q^rnGe my return I have made proof of my new fet of Ml- 
v3 crofcopes, made by Mr Ifilfon^ and have found the 
way of applying them very readily. The contrivance oi 
the ivory Box and hollow Screw for approach, with the 
illuminaring Convex ac the end ot it is of great fervice 
borh by Day aipd Candlelight, and, the Sliders with the 
plain and concave Glafs plates for Objefts very xonvenient. 
But the Brafs Tool I think capable of Improvement, and to 
want it, and when I come on your fide I parpofe to have 
one made with lome inew accommpdations^ a fine 
threaded Steel Screw for a more fteady approach, and fome 
new turns and tfiotions to the Arm which carries the Ob» 
)^Qi^ &c. and I propofe alfo to have a brafs Arm to Aide 
up and down on the fqaare Rod of my deep Microfcope^ 
to which I would with a Screw fix either the Ivory Box, or 
the handle of the brafs Tool, to be fet by that means in a 
fettled pofture, to any bight or inclination required, which 
wils be very necelTary when an illuminating Glafs is applied 
to ticher. 
As for the Glafles thenifelves, I think them very good 
and well wrought^ and ftb$D not ib ipeatly fee) m go far 
beyond any I have fecn oi Meilms: ■ The greateft Magni- 
fiers efpecialiy augrnenc more, and yet fliew an Object^ rnqra," 
diitinft than his. My greateft (hew an hairot niy head, to 
tny Eye conuderabiy above an Inch diameier, and feme 
A a a a a a a u Ey^-"* 
