DECEMBER, 1017. MONTHLY WEATHER REVIEW. 589 THE SETTLEMENT OF TROPICAL AUSTBALIA. 32.5.c (9 4 By GRIFFITH TAYLOR, D. Sc., Physiographer. (Commonwcnlth Meteorological Bureau, Melbourne, Austnlia). [Reprlnlrd/rom The Herald, Melbourne, Victorin, Oct. 27,1917.11 The fundamental problem in Australia is the settle- ment of her empty tropical area. Opinions as to its economic value are most conflicting. A recent report stated that it is "undoubtedly the best and richest por- tion of the continent"; while I have just heard of a returned settler who declared that the 0111 as cct of ironi the stern of a southbound steamer! The truth, as usual, lies between. It is on the whole fair pastoral country-which is very lightly stocked at present. lt has limited areas of rich, a ricultural land- which are prncticnlly untouched. In t h e hinterlands it has numerous mining fields, usunlly of medium grade-many of which liave been abandoned owing to lack of labor. No serious student can doubt that natural resources of very considerable ralue are awaiting exploitateion-but the .great handicap, whether it be actual or only imagined, IS certainly to be found the Territory which plensecl him was that wiich T f ie saw - in the climate.. In the following brief article I shall dwell chiefly on this aspect of the prouhleni, more espeaidy ns i t coiicerns the undeveloped meus in the Territory and Wcst Rus tralin. A ver cursory acqunintnnce with hygienic and econo- climatic features which are most usunlly cliscussed-i. e., average temperature and annual rainf all-are of relu ti vely minor importance. As regards the hunian organism the factor of humidity is of renter importance than temperature. As regtircls as important as the total amount. We can, with comparative ease, map Australia to show the rain reliability fairly accurately. Su pose we consider the annual rainfall a t Melbourne normal in each year. We observe, of course, that in some cases the total annual rainfall is above the avernge (35 inches) a t other times below this figure. If we tnkc these deviations and average them, we find an average devia- tion of 12 per cent from the normal. Thus we niay ordi- narily es ect fluctuations from 23 inches to 25 inches a If now we a ply the same test to the eastern portion Northern Territory-we find that the reliability is much less and the avera-ge deviation is nearly 50 per cent (see the shaded areas in the map). Hence here the rainfall may be anything between 12 inches and 3'7 inches-al- though on the average it is much the same as a t Mel- bmrne. So far as I know those optimists who propose to grow wheat in our tropical lands have given little attention to the season of the rain; and none a t all to it-s reliability as discussed above! As I have shown elsewhere there are some regions where economic wheat growin0 may he ossible in our hot lands-but they are neitKer in the garkly Tableland nor in the south of the Territory. Now let us turn our attention to another factor which is a potent control in tro icd lands. enernlly ment for testing the suitnhility of a region as regards habitability, is the wet-bulb thermometer. mic pro i lems leads one to the conclusion that the two plant 5 .fe the season and reliability of the rain are a t least for a P ong period of years, and find the deviation from the year at 9 elbourne. of the Barkly I p ableland-a vnluable grazing area in the It is accepted by phyvsiologists t g n t the best nvnilub f e instru- 1 Communlcaled by the author. 40093-1&-2 Prof. Gregory has adopted 7S'F. (wet-bulb) as an upward limit-" above which continuous hard work becomes impracticable." I do not agree with him alto- gether, for 7S"B'. (wet-bulb) is quite common along our northern coast-but this statement (b a stron s u p deductions from a char e of exaggeration. adopted 70'F. (wet-bulb) as the limit of conifort for our mce. This means that when the average wet-bulb remains aboye 70'F. clay after day for a Ion period con- ditions are not favorable for close white sett T cment. An open-air, active occupation, such as stock-riding, has little to fear; but strenuous field labor, sedentary indoor life, and especially domestic work and the care of young children cannot (in my opinion) be carried on under f avorable circumstances at present, with continuous high wet-bulb temperatures of this order. Here I shall be met with numerous descri tions as to how " Mrs. Jones raised five healthy children " ; how that cscellent clerk Brown "pines to return to the healthy life in the north", and so on and so forth. These statements are all true-but they do not repre sent average conditions, nor are these sturdy pioneers (to w~hom be all honor) typical emigrants. Close settlcment, uiifortunntely, depends on an influx of average settle?. There is nowhere in the world, so far as I am able to d~s- coyer, n region resembling our northern const lands with an important white settlement. I I porter of tropical white settlement) will ? ree the fo f owing For remons which I % ave elaborated elsewhere, I have how "John Jones lived to 95 and never left t P io tropics"; a 3 0 - FIG. 1.-Important climrrtologieal houndsries lor A!iqtralla. A-B separates the eastrm Iairly uniIonn run region Irom the wcrtem wnter-drought region. Shaded areas have very erratic rains (40 per cent variability). Lines connect oints having the ssmc number 01 months with an a'verd&% wet-bulb temperature 0170' 3, e. g., Thursday Island has 12 months, Rri.ibane,he 2 months 01 that condition. Approximatc scale 01 miles is indmted on the Tropic 01 Capricorn. In the map (fig. 1) I indicate approximate1 how this Many of m rcslders have anat.hcma- reenble a feature of Sydne (and indeed in much less %et Sydne has no month approach an average of months, and conditions become cont.uiuously less attract- ive as we travel up the coast. At Mackay such high wet- bulb temperatures obt,ain for 6 months in the year, at Cooktown for 10, and at Thursday Island all the year round. question of wet-bulb temperatures affects c 3 ose settle- tized those oppressive days in Fe 55 ruary which are so dlsa- $e ree are not unknown in J elbourne). 70' (wet-bul i ). Brisbane has two sufh disagreeable ment in our tropics: DECEMBER, 1917 500 MOSTHLP WEATHER REVIEW. Probably one or two disngrceable months in the year havo no particular efiect on thc well-bcing of the settler- but let us follow the 6-months isopleth on thc map. It runs along the Queensland coast north of Mackay, sweeps to the north of the Athcrton Tableland (that most proniising re ion i n our tro ics!); alon the Gulf W. A. This line is no fanciful creation but is a definitc clinia- tological boundary. Yet I should point out that the unfavorable zone thus niarked out is not all of one type. Anothcr factor comes 111 which, luckily, greatly unielio- rates conditions on t.he Queciislnnd coast. here blow the steadiest onshore winds in the world-the Sout.henst Trades. A high wet-buib temperature, if accompanied by a fresh brcezc, is robbed of half it.s terrors. Unfortu- nately the effect of local winds on health and comfort has not becn inrest.igntcc1 in our tropics, and niy own ex erionce is liniitetl to the Queeiislitnd coast. !having shown that the 6-mont.hs isoplet,li on the map has a r e d climat,ological value, what hearing has i t on tlie settlement of our tropicsf It will hc not.iced that it is precisely the low-lguig rivcr alluvials which arc adversely nft’ected. Herc irrigation may ultinintcly be possihlo, for there are ninny truly fine rivers running into our nort.lieni seas. But I doubt if a white furniing coni- muiiity will settle in these suitable tireas for T-ery maiiy yeais, and this brings nie to tlie last section of t h e article. I hnvc found i t a corn arntively siniplc mnt.t.er (by means of