[99] 



IRcw pboto^mMcroorapbic apparatus. 



By C. Lees Curties. 



THIS apparatus consists of a base-board of sufficient length to 

 take the camera when fully extended, the microscope, and 

 the lamp, and is an inexpensive form of camera, designed 

 by Mr. E. M. Nelson and myself, for use specially with Zeiss's new 

 projection eye-piece. No. 3 ; but can also be used with ordinary 

 eye-pieces, or where a long camera is required, without eye-piece. 



The height of the camera above the base-board is the same as 

 the optic axis of the Nelson model microscope, but can be arranged 

 to the height of any microscope stand. The camera itself con- 

 sists of two millboard tubes, which are light but strong, the one 

 sliding into the other like the tube of a telescope ; the joint 

 between the two tubes is made light-tight by a velvet flap. Whe 

 the tubes are closed, the length of the camera is 2 feet, but it can 

 be used at any length up to 3 feet 6 inches. The outer tube is 

 fastened to an upright frame of wood, which is clamped to the 

 base-board by thumb-screws at any point of its extension ; this 

 tube is removed when the different sized diaphragms are put in 

 position. 



The focussing screens of grey glass and plane glass, with finely 

 ruled diamond lines, slide in grooves at the back of the wood up- 

 right ; a double metal back is supplied which also slides easily in 

 the same grooves. The focussing is effected by a rod placed at 

 the right hand side of the camera, a string passes round this, and 

 over a wheel on the opposite side, taking a turn round the milled 

 head of the fine adjustment. This string is kept tight by a strong 

 elastic band. The feet of the microscope fit into blocks fastened 

 on the base-board. 



The manner in which the apparatus is used is as follows : — 

 The- camera is closed up and pushed back as far as possible. 

 The microscope is then arranged in a horizontal position, with the 

 feet held firm under the blocks on the board. Sufficient room is 

 left between the eye-piece and the opening in the camera to allow 

 the eye of the operator to be placed to the eye-piece. The illumi- 

 nation is now centered and adjusted, and the image of the object 



