158 NATURAL HISTORY. [NORTH 
stituent parts, and easily known by the reddish colour of 
its fractural surfaces: crystallized, massive, and foliated. 
Case 8 contains a suite of specimens of sulphuret of lead 
or galena , which include various modifications of crystals, 
detached and grouped together, in combination with 
blende, pyrites, and many other substances; galena of 
various grain, massive and disseminated; galena of cor¬ 
roded appearance, decomposed and regenerated; the com¬ 
pact and specular variety, called slickenside by the Derby¬ 
shire miners. 
Case 9. Sulphurets continued: sulphuret of bismuth , 
or bismuth-glance, inacicular crystals, from Riddarhyttan, 
&c.— Sulphuret of copper and bismuth , called copper-bis¬ 
muth .—The needle-ore of Werner, a triple sulphuret of 
bismuth, lead, and copper.*— Sulphuret of copper and tin , 
or tin-pyrites .—The remainder of this case is taken up by 
a considerable suite of specimens of sulphuret of mercury 
or cinnabar , divided by Werner into the dark-red (by far 
the most common variety), and the bright-red cinnabar 
(native vermilion, much esteemed by painters); the hepatic 
or idrialine-cinnabar , a mixture of cinnabar with bitu¬ 
minous and earthy particles, from Idria, compact and slaty : 
the same with testaceous organic remains (coral ore). 
Case 10. Sulphuret of silver, vitreous silver, or silver 
glance , massive, crystallized, and in other external forms, 
among which are the laminar and capillary: the black 
silver ore appears to be a pulverulent variety of this spe¬ 
cies —flexible silver glance.— Sulphuret of antimony , or 
grey antimony, compact, foliated, radiated, and plumose : 
the more remarkable among these are the specimens of 
crystallized antimony in splendid groups, especially from 
Transylvania; radiated grey antimony with baroselenite, 
realgar, &c., plumose antimony (feather-ore), some varie¬ 
ties of which, appearing likt delicate wool or down, dis¬ 
play a fine iridescent blue, yellow, and red tarnish: it 
should, however, be observed here, that several of the plu¬ 
mose varieties of grey antimony are referable to the sulphur- 
salts in the next glass case. 
Case 11. Part of this Case is occupied by the speci¬ 
mens of sulphuret of arsenic , viz. the yellow orpiment , mas¬ 
sive and in striated, transparent, separable laminae; and 
the red orpiment or realgar , perfectly crystallized and 
