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-A Simple Photographic Spectrometer. 



Edwin Morrison. 



Photographic spectrometers of several different types can be purchased 

 from instrument makers. Attachments to convert ordinary prism spectro- 

 meters into photographic spectrometers can also be found upon the market. 

 It is the purpose of this article to describe a method of constructing a simple 

 photographic attachment for a prism spectrometer that can be constructed at 

 slight expense in any well equipped laboratory. 



Figure one shows a diagram of the camera attachment. The dimensions 

 have to do with the one I have constructed, and would need to be modified 

 to meet the conditions of available material. That is, the length and diam- 



F '9 ' 



eter of the camera tube is determined by the focal length and diameter of the 

 objective lense used. The figure is largely self explanatory. The section of 

 the tube from C to B is constructed from a piece of wood 3x3x7 inches. A 

 hole is bored lengthwise through this piece. From C to E this hole is 2 inches 

 in diameter, and in order to shut out the stray light from around the focusing 

 tube the remainder of the distance from E to B is 1 % inches. A brass tube 

 T, 2 inches in diameter is carefully fitted into the hole in this piece so that 

 it can be slipped freely inward or outward for focusing purposes. At the 

 outer end of this tube a 1 M-inch, 28 inches focal length, achromatic lense L 

 is mounted. The tube from B to A is a tapering box, 2K inches square at 

 B and 4 inches square at A. This section is constructed from ^-inch lumber, 

 the joints being carefully glued and re enforced by screws to make the box 



