88 MICROSCOPIC ILLUSTRATIONS. 



have been already described as belonging to tbe vertical 

 instrument, will be very briefly referred to here. Let 



Fig. 12. 



Fig. 13. 



Fig. 14. 



e, n, represent its compound body, which may be either 

 achromatic or periscopic ; its lower extremity screws 

 into the bent arm, n, whilst the other arm, a, is suited to 

 receive single or compound magnifiers. The stage, t, 

 on which the object- sliders are to be placed, is remova- 

 ble at pleasure. It is shewn separate by fig. 14. The 

 protruding ears on each side, shewn at, 4, serve to hold 

 by, when putting it on or removing it from the instru- 

 ment. These being in a line with the two stout pins 

 which fit into the block on the top of the stem, c, prevent 

 any strain being occasioned by the operation. This 



