DKKP-SI^V 1:\1'I.oi;atI()N. 1 17 



])y the number ol" rrvoliitioii-^ iiindi' I»y (lu- reel iVoiii wliidi 

 it uncoils, thus savint,^ ji vast amount ol" IVietion between 

 the water and tlie wire-Hne. The moment of touehin<f bot- 

 tom is also nuu'h more clearly indicated by the light reel 

 employeil, which, assisted by the absence of friction on the 

 wire, ceases to turn almost as soon as the weiji^ht touches 

 bottom. It is im|)ossibl(', in the brief account I can give 

 you, to go into the minuter details wliich iiia\' be found in 

 the publications })reviously mentioned. 



This invention has i)roved to be of the greatest import- 

 ance, and, singularly enough, though invented before the 

 celebrated voyage of the Challenger, sent out by the British 

 government, and immediately taken up by Belknap in our 

 own sounding expeditions in the North Pacific, where its 

 value was thoroughly demonstrated, the countrymen of 

 the inventor continued throughout their three years' cruise 

 to use the cumbersome hemp rope in all their sounding and 

 • Iredging work, thereby diminishing the efFectiveness of 

 their operations by at least sixty per cent. 



Partly from the tact that the expense of deep-sea sound- 

 ing expeditions is so great as to place them beyond the 

 means of private individuals or scientific .societies, and 

 partly from the unsatisfactory results and enormous depths 

 reported by naval officers of several countries, governments 

 and scientific bodies remained, until recent years, indifferent 

 or sceptical as to the })racticability of making re.searches in 

 the deep-sea which should produce results at all adequate to 

 the expense involved. 



It was only when the subject of telegraphic communication 

 by cable under the sea assumed a commercial importance 

 which could no longer be ignored, tliat a knowledge of the 

 conditions of the sea bottom, especially in the North At- 

 lantic, became a necessity. Deep-sea exploration may 

 therefore be said to have commenced systematically only 

 about 1850. The survey of the " telegra]>hic plateau" began 

 about this time by the aid of the British and American 

 navy, and even with the comparatively imperfect means 

 then available, a very large amount of information was 

 gathered in the course of the succee<ling four or tive vears. 



