10 Jan., 1918.] Potash. 59 



the most economical conditions. In Australia, the matter has been 

 engaging the attention of the Commonwealth Advisory Council of Science 

 and Industry. The cliief possible sources of potash are: — (1) The 

 ashes of various plants, seaweeds. (2) The water in which sheep's wool 

 has been scoure(J. (3) Brines and residues of salt lakes. (4) Kesidues 

 from the manufacture of cane sugar, &c. (5) Fume, as obtained from 

 cement works as flue dust. (6) Potash-bearing rocks, as alunite, leucite, 

 felspar, mica, &c. 



The Council came to the conclusion that, of all these possible sources, 

 alunite Avas the most immediately promising. It was necessary, 

 liowever, first to ascertain by experiment the best method of extracting 

 potash from the local deposits of this mineral, since each deposit of 

 alunite varies somewhat in composition, necessitating diiferences in 

 treatment. The experiments were carried out at the Melbourne Univer- 

 sity by Mr. F. W. Janes, working under a committee consisting of: — 

 Mr. A. J. Iliggin, lecturer in raetallurgy; Professor Orme Masson, 

 professor of chemistry; and Mr. V. G. Anderson. The results of the 

 experiments, together with much information as to alunite, and 

 especially as to the deposits in Australia, have now been published as 

 Bulletin 3 of the Advisory Council, which can be obtained post free 

 from the Secretary, at 314 Albert-street, East Melbourne. 



There are at present three known deposits of alunite in Australia — 

 two being in South Australia — one at Carrickalinga Head, on St. 

 Vincent's Gulf, about 40 miles south of Adelaide; and the other near 

 Warnertown, 17 miles from Port Pirie. 



The alunite from Carrickalinga Head is of exceptional purity and 

 evenness of composition, with a high and very uniform potash value. 

 In the deposit at Warnertown, though of high grade, yet the proportion 

 of soda to potash somewhat diminishes its value. The third, which has 

 been described as the biggest deposit of alunite in the world, and from 

 which shipments have been made to England for many years, is found 

 at Bulahdelah, 'New South Wales, about 60 miles north of ISTewcastle. 

 Alunite is a hydrous sulphate of aluminium and potassium, but, generally 

 speaking, it contains, in addition, sodium, silica, oxide of iron, lime, 

 magnesia, chlorine, and phosphoric acid. It usually occurs as a 

 massive, finely-granular rock, or in nodular masses, varying in colour 

 from white to red, according to the nature and extent of the impurities 

 present — the pure mineral being white. It is insoluble in all acids 

 except strong sulphuric acid upon heating, but is readily soluble in 

 caustic alkalies. Under varying methods of treatment, and at different 

 temperatures, it yields products of considerable industrial importance, 

 such as potash alum, aluminium sulphate, alumina, potassium sulphate, 

 and sulphuric acid. As potash for fertilization is perhaps at present 

 the most necessitous of our requirements, it may be pointed out that the 

 results of experiments carried out by the Bureau of Soils, Washington, 

 United States of America, show that roasted alunite was, on the average, 

 more effective than either high-grade potassium sulphate or chloride. 

 The increase of crops resulting from the addition of raw alunite was 

 14 per cent., roasted alunite gave 40 per cent., and potassium sulphate 

 and chloride showed about 38 and 31 per cent, respectively, corresponding 

 amounts of potash being used in each case. The best i-esults were 



