48 
NATURAL HISTORY. (Minerals.) 
[north 
these are the specimens of crystallized antimony in splendid groups, 
especially from Transylvania; radiated grey antimony with baroselenite, 
realgar, &c.; plumose antimony {plumosite of Haidinger), some varieties 
of which, appearing like delicate wool or down, display a fine irides¬ 
cent blue, yellow, and red tarnish: the chemical composition of some 
of them is uncertain. 
Case 11. This and part of the next Case contain the simple and 
double sulphur-salts formed by the sulphurets of antimony or arsenic, 
with basic sulphurets of electro-positive metals; among these may be 
specified (besides some varieties of the plumose antimony or feather- 
ore)— ihejamesonite or axotomous antimony glance;—the geocronite of 
Swanberg;— ih^kohelite ; —thehoulangeritedindiembrithite; —the zinck- 
enite, nearly related to plumose antimony ;—the silver-blende, red or 
ruby silver, divided into the dark and the light red, both of the same 
crystalline forms, but in the latter of which sulphuret of arsenic takes 
the place of the sulphuret of antimony of the former;—the miargyrite 
of H. Rose, first separated by Mohs from red silver under the name of 
hemiprismatie ruby-blende ;—to these is related the melan-glance, as 
are some varieties of the sulphur-salt commonly called brittle silver- 
glance or stephanite (the rbschgewachs of the Hungarian miners), 
which appears to oe composed of the same constituent elements as 
the dark and the bright red ruby silver ores, but in different propor¬ 
tions ;— bournonite, a sulphur salt known also by the names of endel- 
lion, and triple sulphuret of lead, antimony, and copper, chiefly from 
Hungary and the Hartz :—the scarce polybasite. There are some 
other substances belonging to this order, such as, in 
Case 12, the fahl-ore or grey copper (a double sulphur-salt, on the 
chemical constitution of which much light has been thrown by 
the researches of H. Rose), crystallized, massive, and disseminated in 
various substances; the more remarkable specimens here deposited are 
those from Hungary. The remaining space in this Case is occupied 
by the following sulphurets — sulphuret of arsenic, viz. the yellow orpi- 
ment, massive and in striated, separable laminae ; and the red orpiment 
or realgar, massive and perfectly crystallized, but decomposing by the 
action of light into an orange-coloured powder;—several of the arsenio- 
sulphurets, such as the arsenic-pyrites or mispickel (some varieties of 
which, containing accidentally admixed silver, constitute Werner’s 
weiss-ertz) ;—the cobalt-glance, massive and crystallized in the form of 
the cube audits modifications, &c., chiefly from Tunabergin Sw^eden;— 
the sulphuret of molybdenum or molybdenite (which has sometimes been 
confounded with scaly varieties of graphites), chiefly from Saxony. 
hi the six following Cases the Oxides of the electro-positive metals 
are deposited. 
Case 13 contains the oxides and hydrous oxides of manganese 
formerly distinguished as foliated, compact, and earthy grey manganese, 
but now, from chemical and crystallographical distinctive characters, 
divided into better defined species, such as the manganite, from Ilefeld, 
Hartz, where it occurs in beautiful fascicularly aggregated crystals; 
the pyrolusite, often seen as pseudomorphous crystals after calcareous 
spar, from Ilefeld; the psilomelane, mostly in botryoidal, reniform, 
and stalactitical masses; the braunite; the hausmannite, &c. ; to 
some of which, but particularly the first two, may be referred the 
