278 MAGNESJAN EARTH. 



earth of Baudiflero to be the moft pure alumen ever found in 

 piedmont; and again in his elements of mineralogy, he men- 

 tions the earth of Baudiflero as native alumen. 

 Contrary to thefc ^acls f° pofitively aflerted by fcientific men fo eftimable as 

 afTertions this Maqucr, Baiime, and our colleagues Gioanetti and Napfon, 

 taTnsnValur^ne a ^ ra » tte d no doubt of the nature of this earth; to which au- 

 at all. thorities might be added the fuccefs with which Gioanetti con- 



ftantly ufed"it in his porcelain manufacture. 



Amorig a number of refearches which I made relative to the 

 artificial fabrication of fulpbate of alumen, I employed myfelf 

 on this earth, and to my great furprize found that the earth gf 

 Baudiflero not only was not pure alumen, but did not even 

 contain an atom of it. 

 I enfe ua*. T ne - 0,vn °f ^audilfero isfifuated atleaft three leagues from 

 tities of fulphu- Ivree and from ^rozo, this laft village, as celebrated for it* 



ret of iron at j ron mines as f or the manner in which they are 'wrought, con- 

 Baudiffcro. . . . *' 1 . , n ., . 



tains in a mountain, among other minerals, an inexhaunible 



mafs of fulphuret of iron of a remarkable purity, whefe there 



is eftablifhed a manufacture of fulphale of iron by the com- 



buftion of the fulphur. 



Efflorefcenccof Qn infpecling this manufacture Iaft year, I was (truck with 



the nefghbouring the Angularly powerful action, which the fplphureOus acid, 



by fulphureous f° rme d by tne combuftion of the fulphur, (and of which a part 



vapours. ■■ expanded itfelf to neighbouring places,) exercifed on the 



great blocks of (tone. 



Thefe ftones were a fort of granite fchiftus ; and the (uU 



phureous acid attacked them fo forcibly that it made them ex* 



foliate, and at laft reduced them to a fpecies of efflorefcence, 



or white powder evidently faline, in which its affringent tafte 



announced fulphate of alumen. 



Probability that This circumftance made me think that if a good argil was 



fulphate oi alu- expofedto thea&ion of the acid it would be alumcnated ; and 



Sght'teadJan- the earth °* Baudiflero, which I believed to be almoft pure 



tageoufly made alumen, being at fuch an inconfiderable diftance, made me 



from the porce- conce j ve the hope of being able to eftablifh with economy at 



Piedmont, a manufacture of artificial fulphate of alumen. 

 V^y promifmg The idea of this eftabliihment appeared to me to befo much 

 JocaJ advantages. tne more fortunate' as there was at the foot of the fame moun- 

 tain which contained the pyrites, a great turbary, which ex- 

 tended almoft as far as Chinfella, that is to lay, almoft to 

 Baudiflero, and which might furnifh fuel at a very fmall ex, 

 J ' ■ • penfej 



