VOL. LXXXVIII.] PHILOSOPHICAL TRANSACTIONS. 2Q1 



minous earth. The muriatic acid, during digestion, seemed to act as little as the 

 2 preceding acids; but on water being poured in, to wash out the remaining por- 

 tion, the liquor instantly became white as milk, with a fine white curdy substance 

 intermixed; the concentrated acid having, in the opinion of the author, extracted 

 something which the simple dilution with water precipitated. The remaining part 

 was repeatedly digested with muriatic acid, and treated with water, as before, till 

 the milky appearance was no longer produced. 



The properties of this white precipitate, Mr. Wedgwood states to be as follows. 

 1°. It is only soluble in boiling concentrated muriatic acid. 2°. It is precipitated 

 by water, in the form of a white earth; which may again be dissolved by boiling 

 muriatic acid. 3°. When nitric acid is mixed with the muriatic solution of this 

 earth, there is no appearance of a precipitate; not even when water is added, pro- 

 vided the nitric acid exceeds, or nearly approaches, the quantity of muriatic acid. 

 4°. The earth is precipitated by the alkalies. 5°. The muriatic solution does not 

 crystallize by evaporation; but becomes a butyraceous mass, which soon liquefies 

 on exposure to the air. 6°. The butyraceous mass is not corrosive to the taste; 

 and is even less pungent than the combination of calcareous earth with the same 

 acid. 7°. Heat approaching to ignition disengages the acid from the butyraceous 

 mass, in white fumes, and a white substance remains. 8°. The white precipitated 

 earth is fusible per se, in from 142° to 156° of Mr. Wedgwood's thermometer, and 

 it is thus distinguished from all the other primitive earths. And, 9 . This preci- 

 pitate cannot be reduced to a metallic state, when exposed to heat with inflammable 

 substances. 



From these properties, Mr. Wedgwood says, that though he cannot absolutely 

 determine whether this substance belongs to the class of earths, or that of metallic 

 substances, yet he is inclined to refer it to the former. Professor Blumenbach, of 

 Gottingen, in his Manual of Natural History, published in 1791, also mentions 

 that he had examined a portion of this earthy substance, by means of muriatic acid, 

 after the manner of Mr. Wedgwood, and that he had obtained a slight precipitate 

 by the addition of water. In consequence of these experiments, the mineralogists 

 throughout Europe admitted the white precipitated substance to be a primitive earth; 

 and we accordingly find, in all the systematical works on mineralogy published since 

 the above-mentioned period, that it is arranged as a distinct genus, under the names 

 of Sydneia, Australa, Terra Australis, and Austral Sand. 



The extreme scarcity of this substance prevented the chemists in general from 

 examining more minutely into the nature of this new primitive earth, till Mr. 

 Klaproth, in the 2d volume of his Additions to the Chemical Knowledge of Mineral 

 Bodies, gave to the public a memoir entitled, A Chemical Examination of the 

 Austral Sand. In this memoir, Mr. Klaproth says, that he had received from Mr. 

 Haidinger, of Vienna, 2 samples of this substance; one of which had a consi- 

 derable quantity of black shining particles intermixed with it, which, though 

 regarded by many as graphite or plumbago, he was inclined to believe to be eisen- 



p p 2 



