IT 



G30 



KEPORT — 188-1:. 





the exact depths of tlie oroan, and bringing- up parts of the soil from their beds, 

 may now be repirdcd as solved.' 



Till' deepest soundiu','- known was taken by Belknap off the east coast of Japan, 

 4,Go5 I'lithoms, a little more than SJ- statute miles in depth, lie took 004 soundings 

 of 1,()UU fathoms or upwards, mean time of dcsrent for the first 1,000 fat lioin.s, 

 10 mins. sees. ; 101 of 2,000 fathoms or upwards, time of descent in tJie second 

 thousand, ll mins, :'A> sees. ; ;!8 of .'5,000 (ir upwards, time of descent for the third 

 thousand, 1'2 mins. 40 sees. ; 9 of 4,000 fatlionis or upwards, time of descent tor 

 tlie fourth thousand, 15 mins. 54 sees. Tiie rate of reeling,'' in by hand was nuiclt 

 slower than now attained by the use of steam jjower, yet it was surprisin<,dy rapid 

 and easy in execution in comparison witli the reelinir in of hemp line. 



In tlie fi'reat depths olf the east coast of .Japan, witli the strong' currents, 

 l^xdkiian's appliances were in fact taxed beyond a ]ierfeclly satisfactory execution, 

 the wir'e ha\iiig' parted on oneoccasion at a depth of -l.t'id-") fathoms, before reticliin;^' 

 the bottom, and ag'ain in reeliiiLr in, afiei' souiidine- in a depth of oj statute miles. 

 Larger wire and heavier ajiparatus can develope beyond a doubt the depths called 

 by the Germans .the ' Tusearora Det']),' As now supposed from the soundings 

 taken, this deep water lies at a mean distance of ll'O miles from, and parallel to a 

 line drawn between the most easterly (Jape of Xi])lion and the most northerly 

 Ivui'ilo Island. This is a general direction of X. 10. hall' X. It appears to be at 

 least 250 miles in length, and is probably mui'h longer. Cajitiiin IJelknap justly 

 says tliat those extraordiinny depths, coutig-iious to a reg'ion of elevations, a I lord a 

 held of operations of great interest to the liydrographer. 



The soundings made by IJelknap comprise an ai'e of a great circle between the 

 northern ])art of the island of Xi])hon, the Aleutian l.-lands, and Piiget tSound; 

 another line between San Diego, Cal., via the Sandwich Islands, and the liay of 

 Yokohama, and a development of the true ocean-bed from Puget Sound to !Saa 

 DicLTO. They reveal a dozen or more submerged elevations, veritable mountains 

 ' full many a fathom deep.' In fact, these soundings furnish the fir.st (Xtended 

 and undeniable development of extraordinary and abrupt ineijualities in the depths 

 (d" the sea far away from the land. \\'e owe this to the inventive genius of Sir 

 William Thomson, and to the professional capacity of Caiitain JJelknap, who not 

 only knew how to make the best use cd" what he was furnished with, but also had 

 the ca]iacity to cure defects in the apjiaratus such as they were. In depths of 

 ;»,000 fathoms he used a detachable sinker oi' 55 lbs. In greater depths he su])]ile- 

 mented this with 20 to (JO lbs. of lead. In order to secure specimens of the bottom 

 in larger (quantity Belknap designed several cups, one of which is now unsurpassed 

 for eiiiciency by whatever moditicatioii or other design, as it did its work ])erfoetly. 



Although at the tinu! these .soundings with wire were determined on, the 

 Superintendent of the Coast Survey of the United States hardly hojied a favoiuiihle 

 result from the use of wire, as it had not been adopted by the ' Challenger,' which 

 had been fitted out for .scientific investigation some months before, yet so able a 

 man of .science was not slow to adopt what Belknap had shown was so admirable. 

 In Sigsbee's ' Deep-sea Sounding and Dredging,' pul)lislied by the Coast Survey, 

 Washington, 1880, we find, chap. 1, ' In Augu.st 1874 the " Blake," Commander 

 John A. Ilowell, U.S.N., was provided with one of Sir W. Thomson's sounding 

 machines for wire.' Commander Sigsbee ia the following months made modilica- 

 tions in the apparatus giving- additional facility and rapidity of execution in sound- 

 ing, but nothing could be added to the accuracy of the results that had already 

 been oljtained by Sir W. Thomson and Belknap. 



In the soundings of the Coast Survey, executed by Sigsbee, Bartlett, Tanner, 

 and others, we have a veritable revelation in the contours and depths (d' our 

 coasts. They have brought to our knowledge the wonderful cleft in the crust of 

 the earth on the line of tiie Hudson River extending 100 miles beyond Sandy 

 Hook. Scarcely less interesting, but not so startling, are the plaster casts of the 

 Gulf of Mexico, and of the Caribbean Sea. It is a grateful duty to indiciite to 

 whom lionour is due that the depths of seas are no longer an uurevealed and un- 

 fathomable mystery. 



