Siderite. 355 



about 12 drachms of this calx, whofe natural 

 colour is white, but it is generally tinged 

 brown or yellow from a mixture of the calx 

 of iron. Mr. Bergman purifies it by repeat- 

 edly abftrading the nitrous acid over it, 

 which dephlogifticates the iron, and leaves 

 the calx of fiderite foluble in the mineral 

 acids, but not in the acetous. 



3. The folutions of it in the vitriolic and 

 marine acids cryftalize, though very diffi- 

 cultly ; it rather tends to form a jelly, parti- 

 cularly if there be an excefs of acid ; the fo- 

 lution in the nitrous is reddifh, and in the 

 marine yellowilh ; all are flowly precipitable 

 by water. 



4. This calx is alfo in fome meafure fo- 

 luble in water, but i part of it requires 1500 

 of boiling water for its folution. 



5. Alkalis, both fixed and volatil, 

 fome adtion on it, and acquire a brown tinge 

 from it. 



6. In the dry way it melts per fe on char- 

 coal, and is not volatil ; it gives glafs a green 

 colour, except it meets phlogifton, and thea 

 the colour is brown. 



Y It is reduced to a regulus by melting it 

 A 3 % with 



