368 POPULAR LECTURES AND ADDRESSES. 



A question has been asked with reference to 

 flying soundings, as to the allowance to be made 

 for the non-verticality of the wire. I have indicated 

 that these are only approximate soundings, but 

 they are sufficiently near for many practical pur- 

 poses, and a little experience gives data for making 

 allowances with considerable accuracy. [This was 

 demonstrated by a diagram on the board. 1 ] With 

 the aid of a little experience of what the wire really 

 does in moving through the water in flying sound- 

 ings, you may obtain very close results. In the 

 Hooper, I believe, the flying soundings in from 

 170 to 40 fathoms were ascertained within from 

 10 per cent, to 3 per cent, of the actual depth. 



I hope my friend Mr. Froude may be induced to 

 take up the subject of the resistance of the water 

 against steel wire. He has apparatus at Torquay 

 by which he measures the resistances experienced 

 by models of ships, which I think might also be 

 applied to the measuring of resistances experienced 

 by wire, and from that some valuable results might 

 be obtained. I have found the resistance in towing, 



1 This demonstration is given in a note on " Flying Soundings " 

 appended to the present article. 



