170 NATURAL HISTORY. [NORTH 
ruby-silver ores, but in different proportions; — bournonite, 
a sulphur-salt known also by the names of endellion, and 
triple sulphuret of lead, antimony, and copper ;—the 
scarce polybasite ; —and in the next case. 
Case 12, the fahl-ore or grey copper (a double sulphur- 
salt, on the chemical constitution of which some light 
has lately been thrown by the researches of H. Rose), crys¬ 
tallized, massive, and disseminated in various substances. 
The remaining substances in this Case are (besides the 
sulphuret of molybdenum or molyhdena-glance) several of 
the arsenio-sulphurets , such as the arsenic-pyrites or 
mispichel (some varieties of which, containing accidentally 
admixed silver, constitute Werner's meiss-ertz); cobalt - 
glance , massive and crystallized in the form of the cube 
and its modifications, &c. 
In the six following Cases the oxides of the electro-posi¬ 
tive metals are deposited. 
Case 13 contains the oxides and hydrous oxides of man- 
ganese , formerly distinguished as foliated, compact, and 
earthy grey manganese ; but now, from chemical and crys- 
tallograpliical distinctive characters, divided into the spe¬ 
cies called manganite , pyrolusite, psilomelane , hausmannite , 
braunite , &c., to several of which, but particularly the two 
first, may be referred the earthy manganese or wad , some 
varieties of which have the property of inflaming spon¬ 
taneously when mixed with linseed oil. * 
Case 14. This and the two following Cases contain 
the oxides of iron. Specular oxide of iron or iron-glance , 
among the specimens of which may be specified those 
from Elba, remarkable on account of their beautiful iri¬ 
descence and play of colours ; the variety in large laminar 
crystals appearing like polished steel, from Stromboli and 
Vesuvius the micaceous iron-ore of Werner, belonging 
partly to this species, partly to the scaly hydrous oxide;— 
red iron-ore , divided into compact red iron-stone and red 
hematite. 
Case 15. Oxydulated iron or magnetic iron-ore , 
massive and of various grain, compact, crystallized, in ser¬ 
pentine, chlorite-slate, &c.; ore from the East Indies, 
which yields the wootz, or salam-steel, remarkable for its 
hardness ; magnetic iron-sand . With the oxides of iron is 
also provisionally placed the cruciie of Thomson; and the 
