378 Trayisactions . — Chemistry and Physics. 



begins to rise, thus indicating that the up current is in the 

 advancing part of the cyclone, and that the rising air is 

 filled in behind from the following anticyclone. Further 

 observations will be needed to make this quite certain, but 

 I think there can be no doubt about the fact, although 

 only this one instance has occurred during the year past, 

 in which the balanced wind-vane has been observed at Fare- 

 well Spit. 



In my paper of the 14th March, 1899, I gave what ap- 

 peared to be the general system of circulation of the atmo- 

 sphere in this Southern Hemisphere. The meteorological 

 observations made by the late antarctic expeditions, by the 

 Belgians and by Mr. Borchgrevinck, have shown that in the 

 winter season a high barometer of over 30 in. is frequently 

 observed as far south as 75° latitude. This indicates clearly 

 that the very low barometer, hitherto always observed in the 

 summer in those regions, is not a persistent fact resulting 

 from some hidden cause, but that it is dependent on a belt of 

 cyclones in about 75° S. latitude, as I have supposed, and 

 that in the winter this cyclonic belt is sometimes displaced 

 nearer to or farther from the pole (probably the former), and 

 its place is occupied by anticyclones temporarily. We often 

 see a similar result in the winter season here. The northern 

 belt of anticyclones is displaced southward, and very high 

 barometric readings are prevalent in the South Island. This 

 has been the case in a very marked degree during this last 

 winter. One result of this displacement this year has been 

 that the peculiar clouds which I have called "fish clouds," 

 and which are usually the precursors of a storm at Welling- 

 ton, have very rarely been observed this year ; south winds 

 have also been unusually prevalent. 



The constant formation of high anticyclones over the 

 region of the Southern Alps of New Zealand in winter is a 

 fact which has not yet been explained. A similar occurrence 

 is observed over the high mountain belt of Norway, and 

 it is probable that the low temperature of these great moun- 

 tain masses is a cause of the descending currents of air over 

 them. 



To summarise, then, the results of my investigations into 

 the motions of the atmosphere of this Southern Hemisphere, 

 we find — 



(1.) That the storms which reach us from the south-west 

 are complete cyclones which circle round from north to east 

 and from south to west while travelling round the earth from 

 west to east, and having their centres usually about latitude 

 50° S. 



(2.) That the old navigators' "roaring forties" or the 

 " brave west winds " are the northerly parts of these cyclones, 



