558 



WICK. 



cylinder 8 inches in diameter and 8| inches high. Light from a small 

 automatic carbon arc, A, made parallel by a lens, L, was transmitted 

 through transverse openings in the cylinder in which were mounted 

 glass windows at G, G. A Hilger spectrograph of the constant devia- 



1 



*N 



Figure 1. 



tion type was so placed that the collimator, C, was in line with the 

 light transmitted through the specimen, S. A cadmium spark, N, 

 was used as a comparison source, and a movable mirror, M, was used 

 to reflect this light into the collimator. 



For the study of liquids, the specimen, S, was contained in an 

 inverted cylindrical glass bottle, as shown in Figure 1, with a narrow 

 neck which dipped into mercury, P, to prevent the mixing of the oil 

 through which the pressure was transmitted, with the solution under 

 observation. When the apparatus was used for the study of solids, 

 the specimen was placed in a brass holder mounted in position S. 



H F R 



J(//7/Wh 



^vwv 



G 



V\A/V\ 



Figure 2. 



The details of mounting the glass windows are shown in Figure 2. 

 The cylindrical windows were cut from a piece of plate glass If inches 

 thick and were so mounted that a rubber washer, R, a short piece of 



