However, we preferred a characteristic corresponding to the solid 

 Hne drawn on the graph. This latter offers the real advantage that the 

 door when in a closed position has a tendency to remain closed and 

 when in an open position to remain open. This advantage is offset 

 by the fact that the maximum couple is now 17%, or J of the couple 

 of the door alone. But as the operating handle of the door is placed on 

 the side opposite to the hinge, and the weight of the door has already 



100% -c 



507.- 



FiG. 21. Graph of variations of hinge moment with angle of opening of door 



been reduced to y by the inclination of the axis, one can easily operate 

 the door with one hand. 



The position of the door, open or closed, must be made secure, so 

 that the oscillations of the bathyscaphe will not make it move. When 

 the door is closed it must be held firmly in its seating for the first 

 fathoms of the dive. Afterwards the pressure of the water will keep it in 

 its conical seating. We have, in the Trieste, one single small screw that 

 can be operated without difficulty with one hand, which serves to keep 

 the door closed. 



[ 168] 



