CHAP. V.] 



DEEP-SEA SOUNDING. 



225 



the vanes. The revolving axis communicates its 

 motion to the indices on the dial-plate c, which are 

 so adjusted that the index on the right-hand dial 

 passes through a division for ever fathom of 



n 



FIG. 43.' Massey's ' Sounding Machine. 



vertical descent, whether quick or slow, and makes 

 an entire revolution for 15 fathoms, while the left- 

 hand index passes through a division on the circle for 

 15 fathoms, and makes an entire revolution during 



Q 



