280 MAGNESIAN EARTH. 



More careful The above unexposed refults engaged me to make a more 

 the naSvewrUu careful examination of the earth of Baudifiero, and Which is 

 the objeft of this memoir. 



At the lime when I found that the fuppofed alumen of Bau- 

 difiero in Canavais, was really a magnefian earth, I knew of 

 no other example of an earth truly magnefmn, but fehsfc of the 

 earth of Salinelle, or of Sommieres, which Berard bid made 

 known (Annulcs de Chimie, Tome XXX IX. p. 65,) 

 Othw fpccimen* In this magnefian earth there is no mixture of any other 

 nefia. UV6 ""^ eart ^ exce P fc fi!ex » and tliat - W a very .fmall proportion, of 

 which fact there are but few examples. But on receiving the 

 twelfth volume of Brochanl's Mineralogy, 1 found that the 

 difcovery of a magnefian earth was announced in it, which is 

 the native carbonate of magnefia found by Doctor Milchel at 

 Roubfchitz in Moravia. From the analyfis which he made of 

 if, and which is mentioned by Broehant, we are afiufed that 

 the native carbonate of magnefia of Moravia is compofed only 

 j of magnefia and carbonic acid in almoft equal parts; but the 



yellowilh grey colour fpolted with black, which Doctor Mit- 

 chel gives to this earth, teems fufficiently to indicate the ex- 

 igence of fome other conftiluent parts. On comparing the 

 characters and nature of the magnefian earth of Baudifiero, it 

 will be eafy to perceive the differences which diftinguim it 

 from the other preceding magnefian earths. 

 Local fituation of The magnefian earth of Baudifiero is found difpo fed in a 

 the earth of ve ; n j n a fteatite rock, of which the mountain is compofed 

 that enclofes it. It is accompanied by an horn-frone, fome- 

 times of a tranfparent pale colour, fometimes, when its de- 

 compofition commences, of a white almoft opaque. In this 

 ftate the horn-flone does not appear to be that of which Doctor 

 Bonvoifin has given the defcription and analyfis, under the 

 name of the Hydrophane of Piedmont. 

 It is found in Our magnefian earth appears in mafies, fometimes in round- 

 maffes, lumps, [fa lumps (mamelonnes) and fometimes in fragments more or 

 " pr rasraents * lefs large'; the lumps and fragments are fometimes, but rarely, 

 tuberculofe. 

 Beautifully This earth is of the moil beautiful white, in which it differs 



yrhite. f rom that of Moravia, of which the colour is a yellowifli grey 



fpotted with black, and from that of Salinelle, or of Sommi- 

 eres, which is of a chocolate colour, 



The 



lMf« 



