Analyfts of the Sydney Earth' fi 



E. The muriatic folution was then reduced, by evaporation, to aSout one fourth ; to 

 which I added a large quantity of diflilled water, which did not however produce any 

 change. 1 then gradually added a folution of pure cryftillized prufliate of potafli, and 

 heated the liquor till the whole of the iron was precipitated ; after which, ammoniac pre- 

 cipitated a loofe white earth, which, edulcorated and made red-hot, weighed 7.20 grains. 

 The iron precipitated by the prufliate may therefore be eftimated at 3.20 grains. 



F. The 7.20 grains of the white earth were digefted with fulphuric acid, and, after 

 the cxcefs of acid had been expelled by heat, boiling water was poured on the faline 

 refiduum. The folution was then gradually evaporated, with the addition of a fmall 

 portion of lixivium of potafh, and aftbtded cryftals of alum, without a trace of any other 

 fubftance. 



G. I now proceeded to examine the 85.50 grains of B. Thefe appeared to confift of 

 filiceous earth, or fine particles of quartz, mingled with a confiderable quantity of the dark 

 grey flilning particles. 



Mr. Wedgwood was of opinion that thefe were a peculiar fpecies of plumbago ot 

 graphite. Profeflbr Blumenbach, on the contrary, regards them as molybdana : and Mr. 

 Klaproth believes them to be eifeitglimmer or micaceous iron ore. 



When rubbed between the fingers, they leave a dark grey ftain, and the feel is utiftuous, 

 like that of plumbago, or molybdjena : the traces which they make on paper alfo refemble 

 thofe of the abovementioned fubftances, but the luftre of the particles approaches nearer to 

 that of molybdsena. 



In order therefore to determine whether or not they confifted totally or partially of mo- 

 lybdxna, I put the 85.50 grains into a fmall glafs retort, and added two ounces of con- 

 centrated nitric acid. The retort was then placed in a fand heat, and the diftillation was 

 continued till the matter remained dry. The acid was then poured back into the retort, 

 and diftilled as before ; but I did not obferve that the grey particles had fufFered any change, 

 nor were nitrous fumes produced, as when molybdxna is thus treated. 



To be more certain, however, I digefted pure ammoniac on the refiduum ; and, having 

 decanted it into a matrafs, I evaporated it to drynefs, without perceiving any veftige of 

 oxyde of molybdsna, or indeed of any other fubftance. 



It was evident, therefore, that molybdaena was not prefent ; and, as the general external 

 charafters and properties correfponded with thofe of plumbago, I was inclined to believe 

 that thefe were particles of that fubilance, and not micaceous iron, as Mr. Klaproth ima- 

 gined. To determine this, the following experiment was made : 



H. 200 grains of pure nitre in powder were mixed with the 85.50 grains, and the mix- 

 ture was gradually projefted into a crucible, made ftrongly red-hot. A feeble detonation 

 took place at each pro]e£l:i©n j and, after a quarter of an hour bad dapfed, rhe crucible 

 was removed. 



When cold, the mafs was porous and white, without any appearance of the i»rk grey 

 particles. Boiling water was poured on it ; and the whole being put into a matrafs, one 

 ounce of muriatic acid was added, and digefted with it in a fand heat. By evaporation it 

 became gelatinous : it was then emptied en a filter, and, being well walhed, dried, and made 

 jedrhot, weighed 75.25 grains. 



Ibe appearance of this was that of a wbke earth, uiA I9 Ih* toueh. Whpn melted 



6 with 



