64 natural history. (Minerals.) [north 
which appears to be 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 laminse ; 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 and its modifications, &c., chiefly from Tunabergin Sweden;— 
the sulphuret of molybdenum or molybdenite (which has sometimes 
been confounded with scaly varieties of graphite), chiefly from Saxony. 
In 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 Ilefeid, 
Hartz, where it occurs in beautiful fascicularly aggregated crystals; 
the pyrolusite , often seen as pseudomorphous crystals after calcareous 
spar, from Ilefeid; 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 
earthy manganese or wad , (a name also frequently given to earthy cobalt 
and to other metallic substances in a state of decomposition,) some 
varieties of which exhibit spontaneous combustion when mixed with 
linseed oil. 
Case 14. In this and the tw ? o following Table Cases are deposited 
most of the oxides of iron :—magnetic iron-ore or magnetite (magnet- 
einsenstein of Werner), a compound of protoxide and peroxide of 
iron, most of the varieties of wdiich are strongly attracted by the magnet, 
w hile some of them possess polarity in a high degree (natural magnets ), 
of which several specimens are here deposited:—among the more 
interesting crystallized varieties may be particularized those from Tra- 
versella in Piedmont: among the granular varieties that from the East 
Indies, wdiich yields the wootz, or salam-steel, remarkable for its hard¬ 
ness ;—magnetic iron-sand. 
Case 15. Iron-glance or specular oxide, among the specimens of 
W’hich those from Elba are much admired for their beautiful iri¬ 
descence and play of colours; the variety in large laminar crystals i 
appearing like polished steel, from Stromboli and Vesuvius;—the 
micaceous iron-ore of Werner, belonging partly to this species, partly 
