352 



GASOMETRIC-MANOMETRIC METHODS 



To make a diver by the method of Boell et al.: 



1, Fuse one end of a suitable length of capillary tubing and draw 

 out a solid tail as indicated in steps A-C, Figure 117. The tail must 

 be light enough not to lose its alignment when the bulb is being 

 blown. 



A 



A 



Ki^ 



B 



1 2 3 4 5 mm. 



D 



D ^^^v^'^^^^'■ 



Fig. 117. Making of diver 



according to Boell, Needham, and Rogers. 



Fro7n Holler (1943) 



12 3 4 5 mm. 



I 1 \ ] I I 



Fig. 118. Making of diver 

 according to Holter. 

 From Holter (1943) 



2. Thicken the walls above the tail (step D, Fig. 117). 



3. Seal the open end and heat carefully over a micro flame 

 while rotating the tube so that a bulb will blow itself (step E, Fig. 

 117). The size of the bulb will be determined by the vol. and tem- 

 perature of the air in the sealed unit. 



4. Cut off the neck at the length desired. 

 To make a diver by the method of Holter: 



1. Connect a long thin- walled piece of rubber tubing to one end 

 of the capillary chosen for the proper inside and outside diameters. 



2. Fuse the other end of the capillary in a micro flame to form 

 a glass drop {A, Fig. 118) or, to economize on capillaries, use waste 

 glass to form a drop and then seal it to the end of the capillary. 

 Take care that no air bubbles are entrapped in the glass. The size 

 of the drop will determine the size of the bulb. 



3. Rotate the capillary and hold it horizontally while heating 

 the drop in the flame. Carefully blow a bulb, moving the end out 

 of the flame so that the heat is applied only to the thick-walled 

 portion of the growing bulb (B, C, D, Fig. 118). 



