226 



SUMMAKY OF CURRENT RESEARCHES RELATING TO 



spectra. The construction and manipulation of the instrument are 

 essentially the same as in the laboratory spectroscope.* The absorption 



Fig 38. 



vessel (fig. 38), in which the depth of fluid can be varied at will, is 

 specially designed for measurement purposes. It unscrews into the four 



* See this Journal, 1898, p. 477. 



