^6 Microscopical Essays, 



The upper part f grs of the Rage, is to be raifed or lowered 

 occasionally, in order to make the center of the objea coincide 

 with the center of the lens at O. 



To delineate objeas, the grey glafs rauft be placed before the 

 large lenfes ; the pidure of the objea will be formed on this glafs, 

 and the outline may be accurately taken, by going over the 

 piclure with a pencil. 



The opake part may be ufed in the day-time without a lamp,, 

 provided the large lenles at AB are fcreened from the light. 



TO USE THE LUCERNAL MlCROSCOPE IN THE E X A M I N AT 10 W 

 OF TRANSPARENT OBJECTS. 



The microfcope is to remain as before : the upper part f g s of 

 the opake ftage muft be removed, and the ftage for tranfparenfc 

 objeas, reprefented at Fig. 4, put in it's place ; the end, Fig. 9 

 and 10, to be next the lamp. . 



Place the greyed glafs in it's groove at the end A B, and the 

 objeas in the flider-holder at the front of the ftage ; then tranfmit 

 as ftrong a light as you are able on the objea, which you will 

 eafily do by raifmg or lowering the lamp. 



The objea will be beautifully depiaed on the grey glafs : it 

 muft be regulated to the focus of the magnifier, by turning the 

 pinion a. 



