On Metallic Minerals. 409 



NOTE 7. 



This mineral is turned up by tlie plougli, and is found 

 in the water courses of a fiehl, (composed of a stiff clay,) in 

 rear of Dr. Mill's house at Sillcry, in the neighbourhood 

 of Quebec. 



It occurs under all of the following forms, botryoidal, reni- 

 form and njamillary, and varies from the size of a nut to 

 that of a large potatoc. These are incrustcd on the outside 

 by a yellowish white coaling. Internally it is bluish black, 

 though not uniformly so exhibiting when broken red and 

 yellow parts. Its stmcture is earthy and it is extremely 

 friable — very adhesive to the tongue and gives out a strong 

 argillaceous odour. Its specific gravity is low, but it 

 absorbs water so rapidly and abundantly, as to hiss, bubble 

 and liave its weight considerably increased after a short 

 immersion ; it does not, however, fall to pieces in water. 

 It yields to the nail and receives a polish from it. It is not 

 magnetic until exposed to a read heat with grease, and then 

 only slightly. Before the blow-pipe it becomes glazed and 

 rounded, fnih borax it forms a glass globule of (he colour 

 of the antethifst, but the greater part of the essay remains 

 suspended in the flux. If too much heat be applied, or if 

 continued long, the coloiu" of the globule is yellow, after- 

 wards it becomes colourless. 



I njay be mistaken in calling this " wad" but it is 

 certainly u combination of manganese and iron. 



NOTE 8, 



Talc and mica, (the silver varieties,) have often been 

 iniijtuken for f>ilvcr. Some years ago, 1 was invited by the 



