August 22, 1884] 



SCIENCE 



147 



The drag-rope proper is tied directly to one 

 handle only, but is connected with the other 



Fig. 3. — The hoisting and reeling engine of the U. R. fish-commission steamer Fish 

 Hawk, showing the supply of wire rope coiled upon the drum. View from for- 

 ward, looking aft. 



not too ragged. It is also cheaply con- 

 structed, and therefore within the means of 

 private individuals. 



The dredges used by 

 the English Porcupine 

 and Challenger expe- 

 ditions were of the 

 same pattern, though 

 somewhat more com- 

 plicated in construc- 

 tion, and much larger 

 and heavier. Judging 

 from the reports of 

 Sir Wyville Thomson, 

 we are also led to be- 

 lieve that they gave 

 much less satisfaction 

 than our own ; and, 

 although many of then- 

 apparent faults were 

 acknowledged by the 

 director in his ' Depths 

 of the sea,' no very 

 great improvements 

 are noted in the narra- 

 tive of the Challenger 

 voyage. All of the 

 changes made by these 



by means of a rope 

 of much smaller size, 

 which, in case of foul- 

 ing on rocky bottom, 

 will be the first to part, 

 enabling the dredge to 

 be brought up side- 

 wise, a not unfrequent 

 occurrence. 



Such, in brief, is 

 the construction of the 

 most important dredg- 

 ing- appliance of the 

 past, and one which 

 will undoubtedly be 

 continued in use as 

 long as marine explo- 

 rations are carried on. 

 For all the ordinary 

 purposes of dredging, 

 especially in moderate 

 depths of water, it an- 

 swers every require- 

 ment ; its flaring mouth 

 causing it to dig slight- 

 ly into sand}' and mud- 

 dy bottoms which are not too soft, and to 

 scrape thoroughly over those of rock when 



Fig. 4. —The forward deck of the U. S. fish-commission steamer Fish Hawk, look- 

 ing forward from the pilot-house, showing the hoisting and reeling enginb 

 and the dredging-boom. 



two important expeditions were apparently in 

 the direction of increasino- or lessening the 



