Microscopes of Poivell, Boss, and Smith. By E. M. Nelson. 553 



on November 21th, 1841 ; it is figured on the frontispiece of vol. ii. 

 of Cooper s Microscopic Journal for 1842. Here we have the first 

 example of the Lister limb with the Jackson rabbetted groove ; this 

 is an excellent form of coarse adjustment, and even to-day it works 



Fig. 148. 



smoothly and steadily ; the stage remains much the same, with the 

 exception of the addition of a non-concentric rotating object-holder. 

 There is an achromatic condenser, fitted with rectangular centering 

 gear, but the substage is dispensed with, and the condenser slides in a 

 Oct. 17th., 1900 2 P 



