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V. — A Simple Form of Spectroscope and Micro-spectroscope. 



By Julius Eheinberg. 



(Read April 21, 1915.) 

 * (Figs. 26-28.) 



In many of the scientific or commercial purposes in which spectro- 

 scopic examinations are necessary or convenient, exact measure- 

 ments are not required ; it suffices to examine the general character 

 and positions of the transmission and absorption bands, and it is 

 usually desirable to examine and compare several specimens at the 

 same time. As a typical instance I may mention the examination 



Fig. 26.— D, diaphragm ; G, grating ; 

 S, slit. 



Fig. 27. 



of coloured solutions and dyed films for photographic filters or for 

 use in microscopy. 



For such purposes I have since many years used the above 

 exceedingly simple form of spectroscope, which not only costs next 

 to nothing, but has several very decided advantages over the 

 ordinary expensive and more or less complicated instruments 

 usually used for spectroscopic examination. 



The spectroscope consists of a tin or cardboard tube of 3-in. 

 diameter, blackened inside, with an adjustable slit at its lower end 

 made of two pieces of metal sheet sliding in a groove. In the 

 upper end of this tube, a narrower tube, blackened inside, is fixed. 



