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VII. — The History of the Micro-spectroscope. 



By John Browning, F.E.A.S. 



Dr. Gayer has kindly afforded rne an opportunity of trying the 

 micro-spectroscope he has contrived and described in the last num- 

 ber of the ' Monthly Microscopical Journal,' the performance of 

 which is very satisfactory. It appears to me only just that I should 

 recall to the members of the Society the fact, that in consequence 

 of a suggestion I received from Dr. Huggins, I have made a micro- 

 spectroscope exactly similar in optical construction several years 

 since. The principal difference in the mechanical details of the in- 

 strument I used was that my spectroscope could be inserted in the 

 body of a microscope, and removed as in the case of an ordinary 

 eye-piece, thus avoiding the necessity of another body for the micro- 

 scope, and reducing considerably the cost of the apparatus. There 

 is an engraving of a contrivance such as I allude to, on page 120, 

 figure 70, in the 6th edition of Mr. Hogg's work on the 

 Microscope. 



My method of finding the object in this micro-spectroscope was 

 as follows : I had a small slot in the body of the microscope and a 

 projecting pin on the adapting tube of the micro-spectroscope. I 

 had an eye-piece with a point or indicator in the field of view. 

 This eye-piece had a steady pin on the side of the tube, correspond- 

 ing to that on the spectroscope. On finding and focussing any 

 small object, bringing it to coincide with this point, removing the 

 eye-piece and substituting the spectroscope, the spectrum of the 

 object was visible at once. 



