NARRATIVE OF THE CRUISE. 



113 



line is hauled in at first, the flap E falls down into a horizontal position, when it is 

 caught by the movable piece of brass F, and is supported on the side opposite to E, 

 by the rod G, which rests on the spiral spring H. The water rushing past E when thus 

 in a horizontal position, exercises a sufficient pressure upon the rod to close the stop- 



Vnrlri-I- 





FlG. 41.- -Stop-cock Water-Bottle, in section, closed and open. 



cocks B, B. When the speed with which the bottle is hauled through the water is 

 increased, the pressure on E becomes so great that it overcomes the tension of the 

 spring H, and F passes the catch G, and the rest of the journey upwards is performed 

 with the flap E hanging down, thus offering the least possible resistance to the 

 (narr. chall. exp. — vol. i. — 1884.) '"' 



