34 



MINERALS AND GEOLOGY 



The colours, &c., communicated to these glasses by the more com- 

 monly occurring constituent bodies, are shown in the annexed tabular 



view. 



Colour of Bead after exposure 

 to an Oxidating Flame. 



BORAX. 



Compounds of 



Colour of Bead after exposure to 

 a Reducing Flame. 



Violet or A m eth yst ine Manganese.... j ^^dff S cS. 



Nickel Grey and opaque 



Blue (very intense) Cobalt , Blue (very deep). 



More or less colorless or in- 

 Green (whilst hot p distinctly colored whilst 



Blue or greenish-blue (cold) . . " hot ; brownish-red and 



opaque on cooling. 



Green or blueish -green Cobalt -r Iron. . . .Green or blueish-green. 



n / j i \ \ Copper + Nickel ) Brownish-red, opaque on 



' j Copper + Iron.. { cooling. 



Emerald-green. 



Yellow (whilst hot) ) v ,. J Brownish (whilst hot) 



Greenish-yellow (cold) j v ' j Emerald-green (when cold). 



Yellowish or reddish Iron Bottle-green. 



Yellowish 

 Enamelled 

 Yellow (whilst hot) . . 



Pale yellowish (cold) Cerium Colorless or yellowish 



Hnamelled by flaming ) I Opaque-white, if saturated. 



Yellow or yellowish-brown 



Enamelled by flaming. . v flamin g- POW' 



V. under phosphor-salt be 



Yellow or yellowish-brown 

 Enamelled by flaming. 

 V. under phospher sal' 



Yellow (hot). . Brown orgrey,semi-opaque 



Colorless or yellowish (cold) . . [ Molybdenum . . ?* ten Wlth se P ara *ion of 

 Greyish and opaque by flaming \ 



fGrey and opaque on cool- 

 L -j ing but after continued 



Y r ellow or yellowish-red (hot) . ' jjl ' ' subjection to the flame, 



Yellowish or colorless, and g., " { 'the glass becomes clear : 



often opaline, when cold . . . ,''"' I the reduced metallic par- 



n ^ I tides either collecting to- 

 gether or volatilizing. 



