THE AMERICAN HISTOLOGICAL STAND. 43 



adjustment as one of doubtful utility; and he once 

 made the remark to a friend, that should he purchase a 

 Centennial, he should insist that the maker furnish a 

 fine adjustment, both front and rear. 



Certain it is that, in the process of correcting a first- 

 class wide-angled objective, it is a convenience to have 

 the fine adjustment at the front. It is, however, ex- 

 ceedingly difficult to so accurately fit the sliding nose- 

 piece that it shall move up and down with perfect free^ 

 dom when acted upon by the fine screw, and at the 

 same time to be free from lateral motion, and this 

 lateral motion constitutes a first-class fault to which 

 the attention of the reader has been called on another 

 page. The very best makers have found it difficult to 

 steer clear of this. The writer once met with one of 

 Mr. Zentmayer's larger stands exhibiting this defect in 

 a marked degree. His own " Grand American Stand/' 

 however, in this respect, is faultless. 



Thus it will be seen that, in the nature of things, a 

 really fine adjustment acting on the nose-piece involves 

 skilled labor, and this, in turn, involves cost. 



Again, the movable nose-piece necessarily changes 

 the length of the body-tube, and this, in turn, again, 

 changes the amplifying power of the objectives, and to 

 get rid of this is indeed " a consummation devoutly to 

 be wished." 



Having had the little Histological in constant use 

 t. e. 9 from six to ten hours daily I arn now prepared, 

 from my own experience, to state that I am quite well 

 satisfied with the fine adjustment as placed by the 



