230 SULPHURET OF LEAD, COPPER, ANt> ANTIMONY. 



testify to Mf Jameson how sensible 1 am of the flattering 

 but unmerited honour lie has 'ys\d me in his mineralogy,, 

 by giving this substance the name $f bouruomte. 



Its characters. ESSENTIAL CHARACTERS of EnDELLION. 



Crysta Ihgraphicai. 



Primitive crys- Primitive crystal. A rectangular tetraedral prism, the 

 td • bases of which are square, and the height of which is t6 



the ide of the terminal faces in the proportion of 3 to 5. 

 Integrant Integrant molecule. I have vet met with nothing to iit- 



piolecule. duce me to adopt any particular opinio*' of the form, that 



belongs to the integraut molecule of this substance. 

 Fracture. Fracture. Irregular, and partially conchoidal. Made 



• ■ < on crystals, and extending but a little way, it is perfectly 



conchoidal. Its lustre is very brilliant. Some of its acci- 

 dental fractures exhibit more clearly than many Of those 

 made by art the direction of its laminae parallel to the faces 

 of its primitive tetraedral prism ; but these traces are al- 

 ways faint, and seldom perfectly marked. 



Physical. 



Spec, gravity. Specific gravity. 5*775. 



Brittkness. Fragility. This substance is very brittle. It is easily 



broken by the simple pressure of the nail. 



Hardness. Hardness. The end ell ion scratches carbonate of lime 



with considerable facility, but not without breaking, on ac- 

 count of its great brittleness. Rubbed on paper it leaves a 

 blackish brown mark. Its powder retains the metallic 

 lustre. 



tblour. Colour. Dark gray, and very shining, like that of po- 



lished steel, but a little more dark. 



Chemical. 



Very fusible. Exposed fo the action of the blowpipe, it fuses the in- 

 stant it is touched by the flame. It remains for some in- 

 stants afterward in a fluid state; and, if it were fused in a 

 spoon, it might be cast like melted lead, the fluidity of 



Hegulus. which in this state it even surpasses. A metallic regulus 



js easily obtained from it, of a dark gray colour, very 



- brittle, 



