MAGNESIAN EARTH. « 325 



prietor of the land where this earth is found, I received a large 

 quantity of it, and we examined it comparatively with that of 

 Baudiflero. 



The earth of Caftellamonte, which was brought to us had When firft dug 

 nearly the fame appearance as that of Baudiflero; but when f^n^colour. 

 it is firft dug up from the ground, it has on the other hand dif- 

 ferent external appearances, which feem to depend on the dif- 

 ferent degrees of decompofition or the Corneen ftone or 

 Cacholong, which is found at Caftellamonte as well as at Bau- 

 diflero. 



The colour of this earth is a white inclining to blueifh. In 

 a mafs this earth is opaque ; but when fmall fragments of it of 

 a minute thicknefs are examined, they have a femi-tranfpa- 

 rency. 



In this refpecl: it has a ftrong refemblance to horn; it is very Refembks horn, 



loft, and may be cut with a knife like hard cheefe. It is more cuts llke ^ ard 



J cheefe, more 



unctuous to the touch, and a little more adhefive to the tongue un&uous, and 



than the earth of Baudiffero. a |j here5 more to 



Treated with the acids, like the foft fpecies of Baudiflero, the firft. 

 it becomes diluted, and then diflfolves, but has however a Does m } effe . r - 

 very remarkable difference, which is-that it diflblves in all t^ie 

 acids without the leaft eflervefcence. 



It alfo does not yield the leaft appearance of carbonic acid 

 on expofing it to the fire in ciofed veilels furnilhed with fy- 

 phons, which communicate with lime water. 



This earth, like that of Baudiflero, does not contain the 

 leaft trace of alumine or of oxide of iron. 



It contains, Similarly to that of Baudiflero, a little fulphate Confifts of the 



of lime and muriate of magnefia, which may be feparated by ^me <ubftances 



& J t J as the firft. 



lixiviatton m water. 



The remainder confifts entirely of magnefia and filex; but But contains ' 

 the proportion of this laft is greater in it than in that of Bau- more filex * 

 diflero. It may be computed at from 10 to 20 hundredth 

 parts. 



When this earth is kept in contact with the air its external Changes its ap- 



charaaers change. P ea / ance °" ex " 



» > pofure to the 



Its colour becomes by degrees a dull white, the fame as has air, 



been remarked of the earth of Bau diflero, t0 a dul1 whit « i 



Its femi-tranfparence is loft; its particles feparate, and in Lofes its femi- 

 two or three weeks it is found to have abforbed carbonic acid tamfparence, 

 t» that degree as to make as marked an eflervefcence with the DO nic acid, fo as 



acid t0 eftervefe wiu> 

 acids, and be 



