xii The Mi cr of cope explained. 
fom of the camera, and you will obtain a lively image 
thereon. 
Now fliut the doors R S, fit down with a pencil in 
your hand, button the band m n upon your wrift, 
place your forehead clofe upon the cufhion a b c, with 
your nofe on the outfide at a, that you may be able to 
breathe the free air; and by this means you may make 
an exadt drawing of every microfcopic objedt that you 
chufe to convey to pofterity, or to oblige your friends 
with your own remarks thereon. 
As the fun appears to move continually towards the 
weft, the brightnefs of the light which furrounds the 
image of the objedt will diminifti on one fide, then turn 
the milled button I, fig. 6. extreamly flow the fame 
way with the fun’s apparent motion, and you will have 
the fame brightnefs as before. This muft be occafionally 
repeated, by which an intelligent reader will inftantly 
difcover, that we have after the above preparation but 
one Angle motion to attend to, in order to preferve a 
proper illumination upon the image of the microfcopic 
objecft intended to be drawn, until its out-lines are com¬ 
plete. From this valuable improvement, all fcientific 
perfons, whofe knowledge prompts them to relate fuch 
difcoveries as their refearches engage them in, will be 
enabled to explain themfelves much better by a picture 
of what they may be deferibing, which they may make 
themfelves, without the affiftance of a draftfman, and 
may by proper letters of reference convey their own 
ideas in fuch an extenfiv^ light, that is beyond the 
power of the moft elegant writer, who, without a draw¬ 
ing, has, or may attempt to make himfelf underftood. 
As we have in this conftrudtion but one motion to 
attend to, in preferving a proper illumination upon the 
image of the objedf, much time and trouble is faved : 
whereas in all the former conftrudtions there are two 
motions to be attended to, and that with very much dif- 
N Acuity* 
