1868.] 



on Deep-sea Dredgings. 



175 



2/°-4 [— 2 0, 55 Cent.]), and of then running southwards until we should 

 find ourselves over the deep valley between the Western Hebrides and the 

 Rockall Bank. In this valley we hoped, from our previous success in work- 

 ing the Dredge at upwards of 500 fathoms, to be able, if weather should 

 permit, to demonstrate the practicability of examining by its means the 

 distribution of Animal life at twice that depth. 



19. After a very fine run of 140 miles in a N.W. direction from the Butt 

 of Lewis, we took a Sounding on the morning of Sept. 15 in lat. 59° 59', 

 long. 9° 15', and found at 650 fathoms [1189 metres] a bottom of bluish- 

 white unctuous mud, very like that from which we had brought up the 

 Siliceous Sponges (§ 16). The minimum temperature here indicated by 

 the mean of three thermometers (registering 45°, 46°, and 47|° respec- 

 tively) was 46° [7°'7 Cent.], the surface-temperature being 53° [11°'6 

 Cent.]. As it was thus evident that we were in the warm, not in the cold 

 area of bottom-temperature, we proceeded about 60 miles still further to 

 the N.W., and on the morning of Sept. 16 we sounded in lat. 60° 38' and 

 long. 11° 7'. The depth was here 570 fathoms [1043 metres] ; and the 

 scoop of the Sounding-apparatus brought up an almost pure G-lobigerina 

 sand. The minimum temperature indicated by two thermometers (regis- 

 tering 46|° and 47i° respectively) was 47° [8°*3 Cent.], the surface-tem- 

 perature being 52°. — Still looking for deeper water and a lower temperature, 

 we proceeded about 50 miles further in the same direction ; and on the 

 afternoon of that day took another Sounding in lat. 61° 2' and long. 

 12° 4', which gave a depth of 650 fathoms [1189 metres]. On this occa- 

 sion our Sinker and three Thermometers were unfortunately lost by the 

 parting of the line in winding-up, so that we did not ascertain either the 

 nature of the bottom or the minimum temperature ; but as we had now 

 reached a latitude far north of that of the cold depths we had previously 

 traversed (being nearly that of the southern end of the Faroe group), we 

 deemed it inexpedient to proceed further in this direction ; and a cast of 

 the Dredge was therefore taken at this point, the depth being greater by 

 120 fathoms than any at which we had previously worked it. We found 

 no difficulty in this operation, notwithstanding that the dredge was loaded 

 with about 2^ cwt. [127 kilog.] of whitish grey mud, of peculiar viscidity, 

 brought up from a depth (3900 feet) nearly equal to the height of the 

 highest mountains in Great Britain. At some 50 fathoms [92 metres] 

 from the dredge, two whitish tufts were seen on the dredge-rope ; and 

 these proved to consist of portions of a Siliceous Sponge, quite free from 

 the mud with which all the specimens previously obtained had been infil- 

 trated. As it is obvious that these specimens must have been detached by 

 the dredge-rope in its passage over the surface of the mud (§ 11), it seems 

 clear that these Sponges, in part at least, project above that surface, which 

 the infiltrated condition of those previously obtained had caused us to 

 doubt. On separating the different parts of the large mass of mud brought 

 up by the dredge, we found it to be everywhere traversed by fibres, which 



