432 



Notes. 



The pinions of the rectangular movements of the stage, though placed 

 at right angles to one another, are both in the same plane as the 

 stage. By placing the fine adjustment lever inside the transverse 

 arm, a far steadier movement is secured. The coarse adjustment, 

 obtained by racking a well sprung and stout triangular bar out of 

 the limb, is a very sound construction, which yields a smooth and 

 steady movement, and which also possesses the advantage that the 

 milled heads of the pinion are brought down closer to the table. 

 Compare this with figs. 112, 113. The substage arrangements are 



Fig. 115. 



the same as in the previous model. There is one feature this Micro- 

 scope possesses which has been generally overlooked, viz. that the 

 body, together with its transverse arm, can be removed, a plain arm 

 can be substituted for the purpose of carrying a single lens or a Wol- 

 laston doublet, so this instrument can be used either as a simple or 

 compound Microscope. About 1847 Andrew Ross moved to 2 Feather- 

 stone Buildings, Holborn, and a-bout 1850 a new model was brought 

 out ; but fig. 115, taken from the 2nd edition of Quekett (1852), 

 plate 11, dated 1851, shows that the general form of the instrument 



