3 26 Voyage of the Nov ar a. 



ther, a variety of interesting observations were made during 

 the passage of the ship round Cape Horn, and numbers of 

 valuable results obtained for the benefit of navigators in those 

 high latitudes. Thus, for example, the fallacy was estab- 

 lished of the assertion of certain navigators that "the fluctu- 

 ations of the barometer off Cape Horn did not depend on the 

 state of wind and weather." In like manner by ascertaining 

 the mean of a variety of collated data, it was found that the 

 temperature of the surface of the ocean demands the most 

 careful attention, inasmuch as the alterations in it from hour 

 to hour may be relied on to indicate corresponding changes 

 in the wind and weather. 



The low reading of the barometer off the Horn seems to 

 be a sort of compensation for the great pressure of the air 

 in what are known to seamen as "the Horse latitudes,'' and, 

 in point of fact, the barometrical readings at 56° S. betray 

 a drooping tendency, which corresponds with the movements 

 of the sun, as the latter also does with that of the zone 

 of greatest atmospheric pressure. Hence it is obvious that 

 from this parallel the atmospheric pressure will increase 

 as we advance to the Pole, and this law is further confirmed 

 by the prevailing winds further south. Hence, while we find 

 north-west or strong west winds blowing off Cape Horn, at 

 the South Shetland Islands, still further south, the prevailing 

 winds are N.E. or E., thus producing contrary atmospheric 

 currents, almost resembling chronic whirlwinds, and conse- 

 quently that both north and south of the central zone, the 



