^'uihfis c/Tm Ora. j.. 



,l,vfis. He treatcdi.b ores with fix parts of potad, in a crucible of lil-.cr iini t'ic IVccdi 

 u-as beyond his expcdations. By the fird operation, 0,91 were re.ui.r.ci foluble in w;.ter. 

 precpitatecl and afterwards taken up by the muriatic acid. The muriate of tin bein. then ck- 

 compofed by carbonate of foda, a pnre oxide was ob.aincd, which was cv.fily re dilTol-.ol 

 tn the ian:e acid, and precipitated by zinc. This precipitate, fufed ,n a crucible with f.ii- 

 low^ afl-ord.d a button of the fame weight as had been obtaltied from the fame kind of ore 

 in the dry way. 



_By this means he was autborifed to conclude as follows, with regard to il:c brown c: 

 O: ScJJackenwald; .., 



rnn - - . ,5 



jjron - - - o.t 



In ICO parts < ., "'' 



]SaIe>c - . - 0,75 



V-Oxygene - . 23,7.5 



100 

 I liare treated in tbe fame manner a cryllal of tin ore of thi^ kind, alfo from Kchiaciv- 

 £nv/ald ; not becaufe I had any <1oubt of the fuccefs announced by a cliemid who has fi» 

 long been in poflelhon of well-earned confidence; but this fuccefc feemed to b,e a eoij 

 iirmation of the co5Jefture on which Mr. lChi,prorh bail founded his experiments, and ! 

 iuppofed that there was good reafon to dojibt whether the complete faturation or (uperfa- 

 turation of tin by oirygene were xke Irue caufc of its infolubility in the muriatic acid. For 

 I could not at ajiy period of the operation difecrn either the fubftance which might feizf 

 this excefs of oxygene, or any trace of the phenomena which mull have accomp"anied its 

 difengagement. 



In order to obferve the circumflances with more facility, I operated in a fmall cruciWe 

 of platina over a reverbcratory lamp of Argand (fur une lampe d'Argand a rccliaut*). 

 Fifty-five centigrammes of the brown cryftals of tin, reduced into fine powder, were well 

 mixed with fix times the quaiuity of potafli purified by alcohol, and dried. The mixture 

 was moiflened with a few drops of water, then evaporated to drynefs, and afterwards 

 Jjcate<l to the commencement of fufion. After the firft operation, hot water was poured, 

 on the mafs, and took up move than half the mineral. Muriatic acid fird precipiiated if 

 and afterwards dillblved it with the greateft facility. The precipitate or metallic oxide, 

 reproduced by carbonate off otadi, was in fad completely folu'ble by t]ic fame acid, as Mr. 

 Klaproth liad alfirmed. 



But after having thus witneffed the facls, my firR doubt concerning the direCl foliilillity 

 of tills ore was rather ftrengthened than removed. For it cannot be affirmed that tiie o.cefa 

 cf oxygcnc was dilfipated ilurlng the fufion with potalli, becaufe the metal could not form a 

 foluble combination with the alkali, but in confei|uencc of its oxidation to the lafi degree, 

 or, to fpeak more correctly, its acidification ; fo that the llxii inm of the filtered n.ndne is 

 a true ftaniute, or perhaps a ilannitc t, of tin (potafli). 

 • Tilt author inrend$ foon to gi\ c a (Icfcription uf <hi» lamp. 



<• iMr. Hatclicn in his pjjit-r on the molybdatc of Itad anil thcinulylKlic .icij, inlcrtcd In thi- I'lnlofoiilijcat 

 Tl,i!i|jftiBn»9f f/'.'ndoii for \',<)<i, cumparti prccifcly tlic :i£lic.ii of tl,c jiinic acid on niolvbdi.nj, 10 Vupcroxy. 

 gtn.iit it, Mih^i which prod-iccs the lame cilci?! on tin. It iiiiy convciM" W InlVrrtd thut lin i. aiidifiul \.\.e 

 /TH'!;.!d.-na. O. 



Vol. I.--M,>RCH ITOS. 4 A I,, 



