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XXXVIII. Improvements in the Hilfnev Type of 

 Spectrophotometer. By F. Twyman *. 



nPHE following- is a description of a Spectrophotometer of 

 JL the Hiifner type to which an addition has been made 

 which converts it into a Polarimeter, by means of which 

 optical rotations can be measured for light of any wave- 

 length in the visible part of the spectrum. Incidentally an 

 improvement in design is described whereby greater accuracy 

 is attained. 



Fig. 1. 



opai 



ZB 



Fi*. 2. 



o^ 



The Spectrophotometer part of the apparatus (shown in 

 plan and elevation in figs. 1 and 2 and in fig 3) was designed 

 and constructed in the workshop of Messrs. Adam Hilger Ltd., 



* Communicated by the Physical Society : read January 25, 1907. 

 Phil. Mag. S. 6. Vol. 13. No. 76. April 1907. 2 L 



