292 Elements of Mineralogy, 



from 7 to 7,45 ; the lighteft is the pureftj 

 it melts the moft readily of all metals ; it i$ 

 eafily diflblved in fpirit of fait or aqua regia, 

 and its folution is precipitated blue or purple 

 \>j that of gold. 



SPECIES I. 

 Native. 



2* The exifterice of native tin has long 

 been queftioned, but it has undoubtedly been 

 found fome years ago in Cornwall in the form 

 of thin flexible laminae iffuing out of a ma- 

 trix of quartz, or regularly cryftalized. Phil. 

 Tranf. 1766. p. 37. and Mr. ^uift 9 a very 

 competent judge, attefts its purity in the 

 Memoirs of Stockholm for the fame year. 



3. To afcertain its purity, Mr. Bergman 

 advifes dephlogifticating it by the nitrous 

 $cid. 140 gr. of this calx wafhed and dried 

 are equivalent to 100 of tin in its metallic 

 form ; the folution will take up the copper, 

 and a fmall proportion of iron which the tiq, 

 may contain, and thefe again may be fepa- 

 rated by boiling ; if there be any arfenic, it 

 wi}l be found in the walhings. 



SPECIES 



