[3] 



FISHERIES OF THE UNITED STATES. 515 



represented and discussed, no further remarks on the subject are necessary, excepting 

 that it may be just to Sir William Thomson to repeat the statement made by Com- 

 mander Sigsbee in the account of his improved machine, that, ' ' in point of accuracy, 

 the original form of the machine by Sir William Thomson was successful from the 

 start, and it is particularly to be understood that the sufficiency of the machine in that 

 respect is fully recognized." 



In addition to his sounding machine, Commander Sigsbee has also introduced many 

 improvements in connection with the accessory appliances used with it. Among these 

 may be mentioned the modification of Captain Belknap's sounding cylinder, and the 

 Sigsbee water-specimen cup, which are fully discussed in the catalogue. 



In moderate depths of water, the Coast Survey generally makes use of an ordinary 

 commercial pattern of sounding lead for recovery, with the Stellwagen specimen-cup 

 attachment ; but in considerable depths a sounding rod or cylinder is employed, in 

 connection with a perforated cannon ball of the requisite weight. This is, therefore, on 

 the principle of Professor Brooke, excepting that the sounding rod now in use is of a 

 later pattern (the Sigsbee-Belkuap cylinder), and the method of attaching the shot is 

 more reliable, as described in the catalogue. 



Turning now to the improvements made in the line of deep-sea dredging and trawl- 

 ing, we find that, prior to 1877, in such dredging operations as were occasionally car- 

 ried on by the Coast Survey, the old methods and appliances were always employed. 

 It remained for the Blake, under Commander Sigsbee, and with Professor Alexander 

 Agassiz in charge of the dredging work, to eifect for deep-sea dredging what had just 

 previously been done for deep-sea-sounding. In fact, during those cruises of the Blake 

 from 1877 to 1880, in which dredging formed an essential feature of the investiga- 

 tions, the methods of deep-sea dredging were almost completely revolutionized. On 

 the suggestion of Professor Agassiz, steel-wire dredge rope was first tried for dredging 

 purposes, in the winter of 1877-'78, and proved a complete success, its great superi- 

 ority over the old hempen rope being soon demonstrated. Its small size (fj- inches 

 in circumference), its great durability, and the greater ease with which the dredge 

 or trawl can be landed on the bottom by its use constitute its chief qualifications. 



It was found that when the common form of dredge fell u t on soft mud or ooze in 

 deep water, it became at once filled or clogged with the bottom soil, from its tendency 

 to dig too deeply into the bottom, and was thereby prevented from doing its proper 

 work. To reme dy this defect, a new style of dredge was improvised (called the Blake 

 dredge in the catalogue), consisting of a rather large and light rectangular iron frame, 

 attached to a scraping mouth frame, of which the scraping edges are straight and 

 not flariug. The dredges of this pattern rest flat upon the bottom and are very effect- 

 ive in their results, on soft materials. 



The beam-trawls were modified at the same time so as to work either side down — a 

 great convenience in deep water, where it is often impossible to lower the ordinary 

 pattern so that it will rest right side up on the bottom. Another important invention 

 of these cruises was the Sigsbee gravitating trap, for obtaining evidence as to the 

 quantity of animal life between any two given depths. 



The dredging explorations of the Coast Survey on the eastern coast of the United 

 States have been of a very interesting nature, and much pioneer work has been success- 

 fully accomplished. Deep-sea dredging was inaugurated May 17, 1887, in the region of 

 the Gulf Stream, off the south coast of Florida, by the steamer Corwin, Count L. F. 

 de Pourtales, then an assistant of the Survey, being in charge of the dredging opera- 

 tions. This cruise was undertaken for the purpose of sounding out a line for a tele- 

 graph cable between Key West and Havana. Only a few dredgings (in depths of 90 

 to 350 fathoms) were made the first season, on account of the breaking out of yellow 

 fever on board the steamer, but "the highly interesting fact was disclosed that 

 animal life exists at great depths, in as great a diversity and as great an abundance as in 

 shallow loater." During 1868 and 1869, the same series of dredgings was continued, by 

 the steamer Bibb, in the- Florida Straits, between Cape Florida and Tortngas, and 



