Some Account , of a new Microfcope . 425 
when fet to the Figure there marked, and 
correfpondent to the Number of the Mag¬ 
nifier made life of, the Silver Speculum re^- 
fledts Light on the opake Objedt to be exa¬ 
mined ; which Object muft either be held 
in the Spring-Tongs at one End of the Wire 
O, placed in the Slit m on the Stage F; or b$ 
put on the Ivory Block P, fluck on the point¬ 
ed End of the laid Wire. The third or 
fourth Magnifiers are fitted: to be ufed with 
the Silver Speculum. 
K. L. M. N. QJ 3 ^R. S. T. V. W. X. Y. 
Z. are different Parts of the Apparatus which 
I think needlefs to delcribe, as all who are 
acquainted with Microfcopes will -know them 
at firft Sight, and others may. inform them- 
ielves either in my former Treatife on thefe 
Subjects, or in the Book which Mr, Cuff 
gives to thofe who buy this Microfcooe of 
him. 
In the Year 1747 a Micrometer for this 
Inftrument was alfo contrived by Mr. Cuff,\ 
being a Lattice of fine Wires, placed (when 
made ufe of) in the Focus of the Eye-Glafs, 
by unfcrewing the Body of the Inftrument, 
As the Readinefs wherewith the real Size of 
Objects may be calculated by this Microme¬ 
ter muff render it valuable to the Curious, 
there needs no Apology for laying fome 
Account of it before them, drawn up and 
given to me by my much honoured Friend 
Martin Folkes , Efqj Prefident of the Royal 
