Microscopes of PotveU, Boss, and Smith. By E. M. Nelson. 557 



known as Messrs. Smith, Heck, and Beck]; and in 1853 they removed 

 to Coral ull. In the Exhibition of 1862 the firm's principal Micro- 

 scopes did not differ at all from the one just described, but there were 

 some new models of which a short account is necessary. First, there 

 was a cheap class of instrument called a " Universal Microscope," in- 

 troduced in October 1861 ; this had a flat circular foot, upon one side of 

 which a stout vertical pillar was fixed ; to this pillar the limb holding 

 both the body and the stage was attached. There was a peculiar kind 



Fig. 152. 



Fig. 153. 



size. 



of -coarse and fine adjustment formed by a lever gripping the coarse 

 adjustment pinion, the coarse adjustment being a chain movement like 

 Ladd's. But the interesting feature in this Microscope was its body 

 (fig. 153), which had three objectives at one end and three eye-pieces 

 at the other ; this seems to be an excellent idea, and it is difficult to 

 understand why it has not been largely adopted. This Microscope, 

 probably on account of its inadequate focusing adjustments, had an 

 ephemeral existence. Secondly, there was a " Museum Microscope " 



