Doubts concertihig the Sydney Earth. 405 



M. Klaproth had two fnmples ; the firft confining for the moft part of black brilliant 

 fcales, which might have been taken for plumbago or carburet of iron, but appeared to him 

 to be ferruginous mica ; the fecond, which contained much lefs of this fubllance, was con- 

 fidered by him as purer, and fubjefled to experiment. 



Tliirty grains were reduced to fine powder. The greyifti colour it naturally poffelTed be- 

 came blueilli by levigation. Upon this powder the concentrated muriatic acid was boiled, 

 and decanted off when cold. New acid was boiled upon the refidue, and this operation 

 was three times repeated. 



The acid after filtration through double paper was not rendered turbid by water gradually- 

 added in fufficient quantity. The mixture, when expofed to heat, preferved its tranfparency. 



By faturating the acid with carbonate of pot-afli, a fmall quantity of precipitate was af- 

 forded in light flocks, which, being collefted on the filtre, edulcorated and dried, weighed 

 3.25 grains. This precipitate being added to diluted fulphuric acid, afforded cryflals of alum, 

 and left a fmall portion of filiceous earth. 



The refidue, which was not afted upon by the muriatic acid, was treated in the dry K-ay 

 ■with three parts, of pot-alh, and afterwards with the muriatic acid. The gelatinous infoluble 

 portion, feparated by the filtre, edulcorated and dried, weighed 19.5 grains. It was filex. 



The muriatic folution, eflayed by prufiic acid, afforded a blue precipitate, corrcfponding- 

 with about 0.25 grains of iron. 



• , From this folution, when decompofed by carbonate of pot-afli, a quantity of alumine was- 

 feparated, which, when edulcorated, and dried by heat, weighed 8.5 grains, and upon being 

 combined with fulphuric acid was totally converted into alum. 



The whole of what this chemift obtained from the fand of Sydney Cove was alumine, filex, 

 and iron, without the leaft indication of any other principle. Though he operated upon 

 thirty grains only, and it was impoffible for him to repeat his analyfis, he obferves that the 

 refult is fufficient to render the prefence of a new earth doubtful. He refers the folution of 

 this doubt to time; and on the fuppofition of error in Mr. Wedgwood's experiments, he is 

 difpofed to think he did not filtre his acid folution before he added water to it, and that the 

 earth depofited by the diluted acid was probably nothing but filex chemically united to alumine; 



Previous to a difculTion of the probability how far Wedgwood could be miftaken in his 

 facls and deJuftions, and on what the difference between his refults and thofe of iM. Klap- 

 roth might depend, I had purpofed to give an abridgment of the paper of the former chemift 

 from the eightieth volume of the Philofophical Tranfaflions. But after having made the 

 fame, and begun my comparative remarks, I found that fo much of thefe lafi: would depend 

 upon the ftricl ftatement of experiments, that I determined to give fo much of the entire 

 paper as relates to the new earth. And this I do the more willingly, as it is not, as I am 

 aware, to be found in any work of general circulation. What follows, therefore, is in the 

 words of Mr. Wedgwood *. 



Analytical Experiments on a Mineral from Sidney Cove in New South Wales. 

 THIS mineral is a mixture of fine white fand, a foft white earth, fomc colourlefs mica- 

 ceous particles, and a few black ones, refembling black mica or black lead, partly loofcj 

 or detached from one another, and partly cohering together in little friable lumps. 



' Phil. Tranf. LXXX. 307. 



Non«- 



