4 88 



DISCOVERY REPORTS 



z, z' Pivoted locking tongues which secure the mechanism frame in position within the box 

 section of the outer body. When turned down they engage behind the bottom angle brass frame of the 

 box section in the left-hand side just inside the doors. 



za, za'. Cutaways in the frame on the left-hand side to form finger grips for withdrawing the 

 mechanism. There is also a circular hole, shown in Plate III, fig. 2, towards the base of the frame b 

 which serves a similar purpose. 



Fig. 16. Perspective drawing of the formalin tank with the lid opened to show the storage spool in position. 



For letter references see text. 



METHOD OF TOWING 



Not only am I indebted to the officers of the Department of Mine Design, H.M.S. 

 'Vernon', Portsmouth, for invaluable assistance in the design of planes and the balance 

 of the machine, but also for kindly carrying out the trials to determine the depth at 

 which the recorder swims for different lengths of rope used and the pull exerted on the 

 rope. 



