W. Traveks. — Supposed Pleistocene Glaciation of New Zealand. 439 



It will be observed, however, that although Sir John Herschell considers 

 his own as the correct dynamical view of the course of the great air currents 

 after their meeting at the equatorial belt of calms, he does not differ from 

 Maury as to the general effects resulting from their meeting. It may be 

 presumptuous in me to attempt to decide between two such authorities, but 

 the climatal condition of the northern part of Australia induces me rather to 

 lean to the views of Mr. Maury. Now, looking to the geographical position of 

 Australia, the cause of its peculiarly dry climate will at once be seen, for its 

 eastern coast, to the northward of the thirtieth parallel, is stretched out in the 

 direction of the south-east trade wind, which only fringes its shores with 

 moisture, whilst the whole of the continent to the north of the thirty-third 

 parallel receives the dry upper polar current in the form of the south-east 

 trade wind. To the south of that parallel the winds are the return, or 

 anti-trades, deprived of a large proportion of the moisture they had absorbed 

 in their passage over those parts of the waters of the North Pacific which lie 

 to the windward of Australia, and restored to a comparatively warm condition 

 by condensation. But they still retain a sufficient portion of moisture, 

 increased moreover in their passage across Bass Strait, to make the climate 

 of Tasmania temperate and agreeable. 



Looking, further, at the geographical position of New Zealand in relation to 

 Australia, and bearing in mind that the return current from the north-east trades, 

 which forms the north-westerly winds of the southern part of our hemisphere, 

 moves in the curves before indicated, it is impossible that any portion of the 

 north-west winds which blow over the southern parts of Australia should 

 reach New Zealand at all; I have little doubt, indeed, that they pass consider- 

 ably to the southward of these islands, and that their most easterly margin 

 would not be found further north than the Auckland Islands. Nor is it at all 

 essential to invoke the heated condition of the surface of Australia to account 

 for the warmth of the winds of the Canterbury plains. The degree of warmth 

 is very much the same as, but perhaps a little greater than, that of the north- 

 west winds of the southern parts of Australia, and becomes sensible in the 

 manner explained by our President. 



I quite agree with our President as to the chilling effect upon the person 

 of these winds as they come off the sea, but it must be remembered never- 

 theless that, as anti-trades, they are considered to be warm winds by physical 

 geographers (see Sir John Herschell's Physical Geography, page 268). 

 I believe, moreover, that the winds in question, before they reach the plains, 

 receive a large amount of additional heat from radiation, for these hot north- 

 west winds are usually preceded by dry, cloudless, and calm weather on the 

 eastern side of the mountains, and I know from experience how extremely 

 sultry the air in the valleys becomes during such weather. It is, of course, 



