tfhe Microfcope explained* xiil 
ficulty, even fo as to make it tirefome to the operator, 
which is here removed. * 
The circular box ADF, is reprefented at fig. 6. in 
the mpft convenient pofition for ufe, the axis I L being 
over the drafts-man’s head, in which cafe his back mult 
be turned toward the fouth, which will oblige him to 
fit between the window and the inftrument, if the upper 
fafh can be pulled down, but if the under fafh is only 
moveable, the box ADF muft be changed, fo that the 
axis 1L may be over the back of the camera, then the 
inftrument may be pufhed clofe to the window, and 
confequently the drafts-man’s back will then be turned 
to the north ; but if a large garden or open plain be near 
the houfe, it will, when the weather permits, be better to 
fit out of the houfe, where no buildings or other obfta- 
cles can intercept the fun’s rays, whence we {hall have 
no interruption from the jatnbes between the windows, 
&c. 
The ufe of the new improved microfcope, ap¬ 
plied to the new pyramidicai camera obfcura, 
■when illuminated at night by a peculiar 
lamp contrived for that purpofe. 
T HIS ufeful invention is the refult of a great many 
experiments that have been made for fome years 
paft, to illuminate microfcopic objects in winter even¬ 
ings, which has fucceeded far beyond our expectation. 
And although we have applied it to the pyramidicai 
camera obfcura, as being the belt form for thefe kind 
of experiments, yet they may be performed in a box of 
any 
* Note, in this application of the folar microfcope, 
vve ituirely omit the fquare plate A, the mirror C, and ferews 
tUJ. 
