15 



eastward of successive low-pressure -ystems over the Southern Ocean, relatively warm iir is constantly 

 being drawn from lower latitudes in front of central ureas of depression, which, after parting with heat in 

 the frigid zone and being still further chilled by the mixing of air of polar origin, leave the Antarctic as a 

 cold wind. 



This exposition of surface wind circulation in high latitudes, which is based on a close examination of 

 the results of observations represented on the daily charts, was offered by the writer in the memoir on the 

 Climatology of South Victoria Land in Part I. of this work. The proposition has since been elaborated 

 and extended to equatorial regions by Dr. W. J. LOCKYER,* who suggests that the warm air currents 

 circulating in front of the baric minima of eastward moving depressions are of equatorial origin, and that 

 after they have traversed the southern and western segments of their circuit they rejoin the westerly air 

 current, and so return by the trade wind circulation to the equator on the eastern side of anticyclones. 



This, as the writer understands it, is in effect the suggestion put forward, and it is a proposition with 

 which, in the main, he is in accord. 



ANTICYCLONES OF TUE Srr.-TKoricAi. I!E[.T. 



In regard to this subject Dr. LOCKYER, in the work already quoted, favours the views held by the lain 

 Mr. H. C. BussELL, F.R.S., C.M.G., in regard to these ocean anticyclones and the high-pressure belt. He 

 believes that in latitudes north of the zone of travelling depressions in the Southern Ocean a train of 

 anticyclones moves eastward, following one another in quick succession, and that in charting the mean 

 results of barometer readings recorded in those latitudes the effect is p-oduced on charts relating to average 

 pressure of permanent areas of maximum barometer within a permanent belt where barometer readings are 

 relatively high. Dr. LOCKYER thinks that anticyclones make the circuit of the globe, forming, dispersing, 

 and reforming during their passage, and that it is in this manner that the temperate zone is bridged, and 

 the union between tropical and polar air circulation established. He supposes, moreover, that between 

 each of the anticyclones the northern segments of extensive cyclonic depressions, travelling eastward, 

 obtrude, while the anticyclones move with them. 



Mr. RUSSELL assumed the rate of translation of these hypothetical systems of high pressure over the 

 Southern Ocean to be about 460 miles per day ; were his theory correct, however, a vessel of average 

 speed running eastward between the 30th and 40th or even the 45th parallels of latitude would be over- 

 taken by a succession of anticyclones. On the approach of each the wind would commence to freshen 

 from some point between South and West with a rising barometer, subsequently veering to Northward 

 with a falling barometer and moderating; and a vessel making the passage homeward from Australia rid 

 the Cape of Good Hope in about the 30th parallel would meet these high-piv>sure svstems, moving in the 

 opposite direction, and experience a similar sequence of changes repeated in rapid succession. 



Now it is well known that the reverse obtains; winds experienced by vessels running eastward 

 commence to freshen from a northerly or north-westerly direction with a falling barometer; back to the 

 south westward or southward with a rising barometer and moderate. 



To the navigator making the passage between the meridian of Cape Point and that of Cape Leeuwin or 

 of Stewart Island the overtaking depressions arc of so marked a character, and the influence they exert 

 upon the progress of his vessel so considerable, that there can be in his mind at least no doubt as to their 

 dominance over the weather. 



The evidence afforded by the synchronous daily charts under notice, as well as by charts of average 

 barometrical pressure, is, moreover, in direct contradiction to Mr. RUSSELL'S theory, while, on the other 

 hand, it can lie proved conclusively by reference to Mirh charts that the anticyclones of the great ocean-: 

 are permanent systems of high pressure. 



It must be admitted, nevertheless, that the appearance over the extreme west of Australia, on the 

 daily weather charts that are drafted, of these antir\-r],ines, month after month, and their regular progress 

 across the island continent conveys the impression that they are visitors from the Indian Ocean and might 

 have formed, as Mr. Ki SSI.I.L supposed, thousands of miles to the westward. 



* 'Southern Hemisphere Surfaee Air Circulation,' by WILLIAM J. S. LOCKVKII, M. \. ((.'nntab.), Ph.D. (Guttingcn). 

 F.R.A.S., Chief Assistant, Solar Physics Observatory. 



