Metals, ioo. Chromium* 313 



IGO. CHROMIUM. White with a (hade of yel- 

 low, very brittle, fpecific gravity : very 



difficult of fufion: gradually oxydating in the 

 nitnc acid, and the oxyde becoming green wuea 

 heated in a dole Vcflel* 



lumbi» Red with a (hade of yellow and a fine orange-yellow 

 ftreak and powder, texture compact, cryllallized in 

 4- Tided prifms. 



Plumbum h xaedruirii Syfi. nat. xii. 3. /. i 34. «. 8. 

 Plumbum fulph et arfen. Wall, fyd. z p 3' 9. » 8. 

 P!um um rubrum. GmeLfvll, » /. 3. />. 367. «. 8. 

 Red lead fpar. Kir<ijuan miner. 2. ^. 214. 

 Red lead ore. Schme'J/er miner, 2. p. ihq, 

 Chromat of lead. Thomjon chem» 4. /. 125. 



Found in the gold mines of Bere/ofrt^r Ekaterinhourg jn Sihe*-ia: 

 the prifms are fometimes ttrminated by 4-fiaed pyramids: 

 luftre or tranfparency hardl) any: it is rather foft, witn. an 

 uneven fraflure, does not efferv.Tce wi.h acids, denepitatcs 

 before the olowp pe leaving a finail port on of lead snd a 

 confiderable remainder of black ilig which gives a green co- 

 lour to borax: fpecific g'-avity from ? 7^0 to 6,020: con- 

 tains, oxyde of lead 65,12. chromic acid 34,88. y^.uquelin, 



'.rri. Brown with an afhy-grey powder and flight metal ic luf- 



tre, melted with potafa and diiTolved in waier impart- 

 ing an orange-yellow colour to the folution. 

 Cisromat of iron. 'Thomjon cbem 4* p 126. 



Found near Gajjin in France^ and in >iherta, in irregular mafTes: 

 colour refenibling that of brown blende: hardnefs fufHcient 

 to fcratch glafs : infoluble in nitric acid, and melts with 

 bornx into a fine green glafs : Ipecilic gravity 4,032 con- 

 tains chiomic acid 43,0, oxyde of iron 34,7. alumina 20,3; 

 iilica 2,0. yauquelm* 



VOL. VIT. -- R r 



