August i, 191 8] 



NATURE 



435 



GYPSUM IN SOUTH AUSTRALIA. 



COUTH AUSTRALIA possesses extensive deposits 

 of gypsum, and the technical importance ol this 

 mineral, when of a sufficient degree of purity, has led 

 the State Department of Chemistry to undertake an 

 investigation of the deposits and of their possible 

 applications. The results of the inquiry are contained 

 in Bulletin No. 7 of the Department, the author of 

 which is Mr. D. C. VVinterbottom. The bulletin has 

 been extended to form a monograph on the subject 

 of gypsum, although it is admitted that, owing to the 

 difhculty of procuring the original journals in Adelaide, 

 the references to previous work are incomplete. Never- 

 theless, much interesting information has been col- 

 lected and brought into a convenient form, so that 

 the publication has considerable value, apart from the 

 special descriptions of local conditions. 



The most important deposits occur in the neigh- 

 bourhood of Marion Bay and Cape Spencer, in the 

 hundred of Warrenben, at the south end of Yorke 

 Peninsula. These are gypsum lakes, dry in summer 

 but covered with water in winter, the mineral forming 

 a compact layer of translucent crystals, resting on a 

 floor of hard limestone. The layer varies from 6 in. 

 to 4 ft. thick, but in one of the lakes a thickness of 

 8 ft. is attained, although the greater part of this, 

 being below water-level, has not yet been worked. 

 The water of the lakes being a strong brine, the 

 mineral as quarried contains salt, most of which 

 washes out when the broken mass is exposed to the 

 weather in the stock pile for a few months. In addi- 

 tion to these massive deposits, sandhills occur at Lake 

 Fowler, in the hundred of Melville, Yorke Peninsula, 

 which are entirely composed of flour and seed gypsum, 

 some of the quarry faces being from 60 ft. to 80 ft. in 

 height, whilst the mineral extends below the present 

 floor-level. Flour and seed gypsum are widely dis- 

 tributed throughout the State, largely in the arid 

 regions, but these deposits have been little worked 

 owing to the difficulties of transport. 



The workings in the hundred of Warrenben are 

 already fairly extensive, and modern methods of 

 quarrying, blasting, loading, and shipping are em- 

 ployed. Whilst the inferior qualities, including those 

 which occur in the form of flour and seed, may be 

 used as fertilisers, only the purer mineral has been 

 converted into plaster of Paris, this being its most im- 

 portant technical application. Attempts had been made 

 to manufacture plaster in Australia for many years, 

 but without much success, and until recently the Aus- 

 tralian requirements have been supplied by importation 

 from Germany and the United States. Several com- 

 panies have been formed since the outbreak of the 

 war and are successfully producing plaster. There 

 are now two plaster mills in South Australia, two in 

 Victoria, and one in New South Wales, all using South 

 Australian gypsum. Both the rotary calciner and the 

 kettle process are in use, and a preliminary washing 

 of the crushed rock is necessary in order to remove 

 soluble impurities and fine, slimy calcium carbonate. 

 Organic matter is always present, and greatly in- 

 fluences the quality of the product, since a pure white 

 plaster is desired for most purposes, and the whiteness 

 is readily destroyed by even slight charring of organic 

 impurities. Such charring is most serious in the kettle 

 process, as in this case the material is not reground 

 after calcination ; whilst plaster made in a rotary cal- 

 ciner, although darker at first through local over- 

 burning, loses its colour in the subsequent regrinding. 

 On the other hand, overburning is more easily avoided 

 in the kettle process, and it appears to yield a product 

 with a more uniform rate of setting. Tables are 

 given in which a large number of Australian and 



NO. 2544, VOL. lOl] 



imported plasters are compared in regard to setting- 

 time, colour, mechanical strength, and other proper- 

 ties, the chemical analyses being also included. Ex- 

 periments in the preparation of plaster from seed and 

 flour gypsum are described, and recommendations as 

 to the precautions to be taken to ensure a good and 

 uniform product are made. Given sufficient care in 

 manufacture, the Australian deposits are quite capable 

 of yielding plaster of the highest quality. Charred 

 organic matter and hygroscopic salts are the most dele- 

 terious impurities. 



In view of the absence of deposits of sulphur or of 

 high-grade pyrites from South Australia, the possibility 

 of using gypsum as a source of sulphuric acid is dis- 

 cussed. Many processes have been patented, but none 

 has so far emerged from the experimental stage, 

 although the preparation is quite feasible, and may, 

 in the face of the necessity for obtaining sulphuric acid 

 from local sources, prove to be of some importance. 



THE CLAIMS OF GERMAN IRON- 

 MASTERS. 



CIR ROBERT HADFIELD has done the nation 

 •^ excellent service by issuing a translation of the 

 report of the general meeting of the Association of 

 German Ironmasters held in April last. The report 

 gives an account of the discussions at the meeting 

 and of the speeches made at the dinner which fol- 

 lowed it ; there appear to have been only two papers 

 submitted, namely, "The Share Borne by the German 

 Ore-bearing Beds in the Maintenance of the Home 

 Iron and Steel Industries" and "The Reserves of 

 Coal in Germany as Compared with the World's 

 Reserves"; these are given in the report only in 

 brief abstract, but their tendency can be well gathered 

 from the discussion upon them. The whole of the 

 second paper may probably be looked upon as sum- 

 marised in the one sentence, "Germany in any case 

 is the coming country in Europe"; it may, however, 

 be noted that the author of that paper looks upon the 

 coalfields of Belgium and Northern France, now in 

 German hands, as valuable pledges to be used in the 

 ultimate peace negotiations. Another speaker em- 

 phasises the impossibility that a nation with a pro- 

 duction of twenty million tons of coal {i.e. France) 

 should be able to conquer Germany with its produc- 

 tion of more than 300 million tons ; he must rate 

 the intelligence of his audience very low if he thinks 

 that it will not carry this comparison far enough 

 to add the coal production of Britain and of the 

 United States to that of France. Where would his 

 comparison stand then? 



The second paper constitutes a variant upon the 

 theme which we have heard before : the imperative 

 need that the French Briev and Longwy iron-ore 

 fields should be retained in German hands, being the 

 " essential natural requirement," in view of future 

 wars of the German Empire — " Empire that has been 

 attained by blood and maintained by blood," as one 

 of the speakers at the dinner called it. Of course, 

 the demand for the retention of these iron supplies 

 is masked by the pretext that it is put forward in 

 the interests of the German working-man ; no hint 

 is given that it is the vast profits to be derived from 

 these rich iron-ore fields that the German iron- 

 masters have all along had in view. No one who 

 knows anything of German economics can doubt 

 that this war could never have been begun had it 

 not been for the willing concurrence of the great 

 German ironmasters — and the price that they de- 

 manded for their assistance has now been made 

 plain. Moreover, if it be true, as rumour persistently 



