﻿•> 2 G a y 1 ü r d : Coiuplete Photo - micrographic Apparatus. XVI, 3. 



screw arrangement. To tlie onter is attached tlie pin {j)). By 

 rotatiug- j) tlie outer tiibe slides forward and enters the cap {g). 



When the camera is swung away the tube {p) is with-drawn 

 and the camera Swings clcar, The microscope is clamped fast to 

 tlie table by a block and screw (r). 



The snpport for the illuniinating apparatus consists either of a 

 simple prisme stiffened by a tube as in figure 1, or a raore complete 

 arrangement is that in figure 2. In figure 1 a simple attachment for 

 acetylene gas is shown, and in figure 2 a Thompson 90^ arc light. 



The 90^ arc light is especially suitable for photomicrography 

 as the negative carbon is always in the optical axis, which insures 

 prolonged centering of the crater. 



The illuniinating support shown in figure 2 consists of a strong 

 brass tube fastened to the microscope table by a bracket. Upon 

 this tube are placed the various parts of the illuniinating apparatus. 

 The electric arc light l may be adjusted for lieight by rack and 

 pinion. The head of the pinion is seen at a. The arc lamp is 

 supported by a bracket {b) and may be revolved about a vertical 

 axis at {b). The bracket {b) is fastened to a tube, which is fitted 

 into the tube of the illuniinating bench which is split and re-inforced 

 l)y the clamping ring (c). The arc lamp may be swung under the 

 bench by loosening the screw (c). 



The various parts upon the bench may be adjusted vertically 

 by rack and pinion as at d. They may be adjusted transversely 

 by a slide and screw at T T T. On the Upper surface of the tube 

 formiug the bench is cut a longitudinal slot. On each support is 

 a small key (e e e) which engages this slot and determines the 

 Position of the support. The supports are clamped fast by the 

 screws L L L. If it is desirable to dispense wich-any part of the 

 illuniinating apparatus, the screw L is loosened, the key e is raised, 

 and the support swing beneath the bench. 



In photography with low powers (Micro-collinears of Voigt- 

 länder u. Sohn and Planars of Zeiss) the arrangement shown in 

 figure 2 is convenieut. The microscope is removed, the objective 71 

 attached directly to the camera front board and a large movable 

 stage k is attached to the camera. The stage proper is of glass 

 supported by a metal frame. The coarse adjustment is accomplished 

 by moving the stage in the rod o and is clamped in place by the 

 screw jj. The fine adjustment is liy rack and pinion at /. The 

 complete stage is detachable and is fastened by the screw m. 



