VARIOUS. 



marble* although it yields no sparks with steel. 

 In the places where it borders on the chalky stone, 

 it melts into it by gradual shades. Under the 

 blow-pipe it is changed, though difficultly, into 

 a beautiful white scoria, besprinkled with small 

 bubbles; the fusibility of which, expressed by a 

 globule equal to 0,3, answers to the 189 degree 

 of Wedge wood. 



" It effervesces in the nitrous acid with many 

 little bubbles; and a small piece, of the thick- 

 ness of a line, after remaining in it twenty-four 

 hours, is found to have lost much of its hard- 

 ness, especially at the surface ; it even stains a 

 little brownish, and breaks between the fingers, 

 without however being reduced to powder. Its 

 fusibility is then only 0,13, or 581 degrees of 

 Wedgewood. 



" According to these characters, it is a kind 

 of the stone which I have described in 1524, by 

 the name of silicic alee. 



" The nodules (3) enclosed in that brown 

 stone, are of a fawn-colour, translucent, hard, 

 their fracture perfectly conchoidal, smooth in 

 some parts, a little scaly in others, having, in 

 short, all the characters of true flint, or of the 

 feuerstein of Werner. 



" These nodules of flint are scattered in the 

 brown stone; yet they more frequently occupy 



