Figure 41. Helical mounting mechanism of Negretti and Zambra. This mechanism
was meant to cause the reversing thermometer of Negretti and Zambra to flip at
the required depth. The helical screw would measure the depth on the way down
and release the mounting at the desired depth. James Ferguson of the CHALLENGER
modified this mechanism and tested it in the Sulu Sea at over 4000 meters
| 
