COLLECTION OF MINERALS. 3oi 



of solid and liquid bitumens ; amongst the most 

 curious is that which comes from England, under 

 the name of elastic bitumen. 



Black coal is one of the most precious minerals 

 for its usefulness. The French territory abounds 

 with mines of it, which are worked with ad- 

 vantage. Jet is of a more brilliant black than 

 coal ; it is polished and used for different pur- 

 poses, but chiefly as ornaments for dress in 

 mourning. The yellow amber has been much 

 used in making ornamental furniture ; it is now 

 cut in the same way as precious stones. Pieces, 

 similar to those placed here, are particularly 

 sought by the curious, for the insects that were 

 enveloped by the amber when in its liquid state, 

 without injuring their form. 



With the thirty-fifth case commences the class 

 of metallic substances. Their utility in the arts 

 and their properties are too well known, to ren- 

 der it necessary to enter into long descriptions, 

 to enhance the value of those principal sources 

 of our wealth. We will limit ourselves to a 

 rapid notice of them, merely remarking those 

 most worthy of our attention. 



Platina, which first presents itself, is the least 

 fusible of all the metals; it takes a perfect and 

 tolerably brilliant polish ; as yet it has only been 

 found in the form of little grains, such as are now 



