SELECTION AND USE 



A peculiarity of this microscope is found in the method by 

 which the pillars which support the arm are attached to the 

 foot. Instead of being screwed directly to the foot or cast on 

 it, as is sometimes the case, they are screwed to a circular plate 

 which rotates with a smooth and firm motion. This enables 

 the microscopist to place the horse-shoe either behind the 

 stage, when the instrument is used in a horizontal or greatly 

 inclined position (as shown in the engraving), or in front of it 

 when used in a vertical position. This confers great steadiness, 

 with a comparatively light and convenient base. 



As our purpose is not to give a minute description of any of 

 these stands, but merely to call attention to their characteristic 

 features, we omit all mention of the very ingenious devices 

 which Mr. Wale lias introduced into its construction, such as 

 his new form of iris diaphragm, etc. 



The advantages of this general form of stand are, that it is 

 low and compact, so that it can be easily used in a vertical 

 position a favorite method with physicians and histologists. 

 And so generally has it become a favorite, that most of our best 

 makers have found themselves compelled to furnish micro- 

 scopes of this model in order to retain their customers. Gru- 

 now, McAllister, Zentmayer, and others in this country, and 

 even such English makers as Beck, Crouch, etc., have recently 

 begun to manufacture microscopes of the Continental model 

 in addition to their other styles. 



The Jackson Model. This model is a very general 

 favorite both with English and American makers. It has 

 been adopted by Beck, Crouch, Gundlach, McAllister, Boss, 

 Spencer, Tolles, Zentmayer and others. The new models 

 manufactured by the Bausch Lomb Optical Company, under 

 the superintendence of Mr. Gundlach, are of this pattern, and 

 as an illustration we have taken their Student stand, which is 

 shown in Plate II. The binocular microscope of Mr. Crouch, 

 (Plate IY),*is also constructed on this model. It will be observed 

 that the body of the microscope is supported along its whole 

 length by means of the arm, which is hung between two pillars, 

 so as to give great steadiness. To add to this steadiness, all 

 sharp angles are avoided, and the arm is gracefully curved in- 



