BY FRITZ NOEtIiNG, M.A., PH.D., ETC. 3I 



Specimens of red ochre are by no means common. 

 This is rather remarkable considering its frequent use. 

 For instance, so far I have found only a single piece 

 near Mona Vale, though to judge from the number of 

 tronattas left this must have been a much-used camping- 

 ground. Altogether I found 17 pieces, whidh cannot be 

 considered a large number. 



I have not been able to examine the specimens 

 ■chemically, but the n^acroscopical examination is suffi- 

 cient to prove that the red ochre must be a ferruginous 

 substance. All specimens are strongly adhesive to the 

 tongue ; in other words, they absorb water readily, and 

 are therefore hygroscopic. When broken they show an 

 inner core of black colour, covered by a crust of in- 

 tensely red colour. The thickness of the red crust varies, 

 but so far I have not found any specimens in which it 

 exceeds ]/i^ indhi of thickness. These observations prove 

 that the red ochre represents an iron ore, probably 

 lini'onite (2 Fe203+3H20), but also that the natural 

 mineral has undergone a certain change, by which some 

 of the water was removed. The dark brown natural 

 colour of the limonite is superficially changed into a 

 blood-red colour. The naturally non-hygroscopic 

 limonite has been turned into a hygroscopic substance. 

 The only way of producing such a change is by expos- 

 ing the mineral to heat — in other words, by roasting it. 

 That this view is correct is conclusively proved by the 

 examinations of the specimens, all of which are more or 

 less fire cracked. 



We have therefore ascertained the important fact 

 that the red ochre as used by the Aborigines is not a 

 natural, but an artificial produce, being the result of 

 roasting certain suitable iron ores in the fire. 



The Aborigines had therefore already made an in- 

 vention, which indicates a certain amount of logical 

 reasoning. They discovered that when a certain heavy 

 stone of dark colour is intensely heated, its surface 

 changes into a red earthy substance. This invention 

 may have been made accidentally, but it certainly shows 

 a certain amount of observation, resulting in the subse- 

 quent extensive use of this red earthy substance instead 

 ■of the material originally used for ornamental purposes. 



