MICROSPECTROSCOPE 



137 



means of shellac or balsam. The short pieces of tube fit snugly 

 into the hole in the cork and are pressed tightly against the object 

 slide. The tubes are thus easily removable and readily cleaned. 



70 



4 5 ( 



Scale Divisions 



10 



FIG. 68. Calibration Curve of a Seibert Microspectroscope. 



Or we may employ a cell of the type devised by Andrews. 1 This 

 consists of a glass tube about 2 cm. in diameter and of any con- 

 venient length (see Fig. 69) cemented upon an object slide with 

 DeKhotinsky cement. The observation tube about 5 mm. in 



Dr. W. W. Andrews, Regina, Canada. Unpublished manuscript. 



