TIDES AND CURRENTS. 67-5 



far as 78° N. lat., north of Nowaja Semlja, and their intention at 

 the second expedition was to investigate this sea in an easterly- 

 direction, taking the Siberian coast as basis, and depending on 

 the influence of the great Siberian rivers, whose great quantities 

 of comparatively warm water probably free the coast from ice 

 almost every summer. 



" Unfortunately the year 1872 was one of the most unfavourable 

 ever seen. Already in 74*5° N. lat. the explorers found ice; 

 they could only reach Cape Nassau with great difficulty, and 

 were finally blocked up by packed ice in a locality where, in the 

 previous and following years, there was no ice for one hundred 

 German miles round. They never got within the reach of the 

 Siberian rivers, and the uncertainty with regard to their influence 

 upon the ice along the Siberian const is still the same as ever. 

 But one point is clearly proved, namely, that the conditions of 

 ice between Spitzbergen and Nuwaja Semlja are highly variable 

 from year to year ; this circumstance, more than any other, 

 speaks against the advisability of future expeditions to be made 

 on the basis of Franz- Joseph's Land. In 1874 the explorers 

 found the ice again in the same position as in 1871 ; there is 

 perhaps a certain periodicity in this. 



*' Lieut. Weyprecht formerly thought that marine currents were 

 the principal cause of the general motion of the ice in Arctic 

 regions ; he is now of a different opinion, as he maintains that 

 during the drift of their vessel, which was frozen in, in packed 

 ice, and drifted in this state for over fourteen months, the in- 

 fluence of currents was imperceptible compared to that of winds 

 upon the drifting ice. The existence of Gulf-stream water in 

 the great area between Norway, Spitzbergen, and Nowaja Semlja 

 is undeniable ; the current cannot, however, be traced directly 

 by its course, but rather by the unproportionally high sea- 

 temperatures in those high latitudes. As a natural consequence 

 of this, the Gulf stream does not regulate the limits of ice, but 

 the ice, set in motion by winds, regulates the limits of the warmier 

 Gulf-stream water, depriving the same of the last degrees of heat 

 which it contains. A comparison of the Hansa drift with the 

 winds would show whether on the east coast of Greenland the drift 

 of ice is only produced by the latter ; Sir L. McClintock proves 

 with figures that this decidedly is the case in Baffin's Bay. The 

 speed of the drift of course depends upon the force of the winds, 

 local conditions, vicinity of coasts, and the more or less open water. 

 The great influence of the wind upon the ice-fields is explained 

 by their ruggedness ; each projecting block represents a sail. 



'* In the vicinity of coasts it is somewhat different ; immense 

 currents are often perceived there, originating through the tides, 

 or perhaps through the motion of the ice itself and the winds. 



" There is a decided general tendency in the ice to move south- 

 ward during the summer ; the reason of this may be the flowing 

 off of melted water in all directions, which causes a breaking-up 

 of the whole Arctic mass of ice. But all other influences upon 

 the motion of the ice are nearly imperceptible Avhen compared to 

 that of winds^ and can only be traced in their most general effects. 



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