ZOOLOaY AND BOTANY, MICROSCOPY, ETC. 



309 



Br. Burdon-Sanderson * modified Strieker's stage by the addition of two 

 pipes for passing gas into the central chamber, and a rod for heating the 

 stage by that method if desired. As modified it is shown in fig. 68, and 



Fig. 68. 



in use in fig. 69. In the vessel the water is maintained at a constant 

 level, indicated by the dotted line, and at boiling temperature, a is the 

 supply tube, h the waste tube, c the tube leading to the stage, and d a 

 tube by which the hot water leaves the stage, terminating in a conical 



Fig. 69. 



dropper e. A funnel / collects the drops which fall from e, and g is the 

 waste. The rate of flow is determined by varying the height of e by 

 means of the sliding screw on which it is supported. It admits of more 

 exact adjustment by means of a fine screw which works in the axis of the 



* Burdon-Sanderson, op. cit., pp. 15-6, fig. 3 ; Quart. Journ. Micr. Sci., x. (1870) 

 pp. 366-7 C2 figs.). 



