208 



Staff Commander T. H. Tizard. 



[May 10, 



either decreases to the bottom, or a lower temperature is found at a 

 similar depth. These differences, though slight, give reason for 

 believing that the flow of water from the Antarctic is impeded by 

 submarine ridges. The Arctic water is apparently quite cut off from 

 the general oceanic circulation, excepting at the surface^ and to a 

 depth of 200 fathoms. 



Tides. — When the weather was favourable, and the dredge or trawl 

 was down, we noticed, more especially in the western part of the 

 Faeroe Channel, a regular tidal set, the greatest strength recorded being 

 three-quarters of a mile per hour. The direction of the tidal stream 

 appeared to vary considerably, and unfortunately our opportunities 

 for observations were few, for, as a rule, the long swell usually 

 experienced entirely masked the tide, the " Triton " being so light, 

 that on almost all occasions when the engines were stopped, even 

 with the trawls down, the normal position was broadside to the swell. 

 The height of the waves usually experienced was from 9 to 12 feet, 

 but waves of 17 feet from trough to summit were not uncommon, and 

 early in September, during a gale, they were recorded as 25 feet from 

 trough to summit. 



The highest wave recorded during the voyage of the " Challenger " 

 was 23 feet from trough to summit. 



At all times we noticed that the sea was shorter and heavier on 

 the Wyville Thomson ridge than on either side, arid sometimes when 

 crossing it we observed peculiar "smooths," as if oil was floating on 

 the surface, or a spring welling up from the bottom. In these 

 smooths the temperature of the water remained unaltered. 



ID r edgings and -Trawling s. — The result of the dredgings and trawl- 

 ings, as well as of the surface dredgings, by the tow net, will be 

 reported on by Mr. John Murray, who accompanied the "Triton" 

 throughout her exploration of the Faeroe Channel. 



