856 
SECOND REPORT—1832. 
of Mohs, in 1820, appeared also a “ Characteristik” by another 
excellent mineralogist, likewise a pupil of Werner,—Breit- 
haupt. Whether this coincidence is to be looked upon as 
an indication of the general tendency of thought in the school 
of Freiberg, and how far it resulted from any more direct com¬ 
munication, it is not necessary here to determine. Since that 
time Professor Mohs has removed to Vienna, to superintend 
the Imperial Cabinet, and Professor Breithaupt has succeeded 
him at Freiberg; so that the “natural history method’' is now 
taught to no small or insignificant portion of the mineralogical 
students of Germany ; and the translation of Professor Mohs’s 
Treatise by Mr. Haidinger (1825), enriched as it is with much 
valuable additional mineralogical information, has done all 
that could be done for the diffusion of the system in this 
country. 
Berzelius may be considered the head of the chemical classi¬ 
fiers, as Mohs is of the natural history classifiers. In 1816 he 
published his Essay to establish a purely Scientific System of 
Mineralogy by means of the Application of the Electro-chemical 
Theory and the Chemical Doctrine of Definite Proportions . 
In this Essay he proceeds upon the great principle of his 
school, that the relation of electro-positive and electro-negative 
is the foundation of all chemical relations. Of the strict truth 
of this principle chemists must decide ; the application of it to 
Mineralogy was made with great consistency. Minerals were 
arranged into families according to their electro-positive ele¬ 
ment, and these families disposed according to the place of 
this element in the general electro-chemical scale. Thus there 
was a family for sulphur, another for azote, another for carbon; 
others for each of the electro-negative metals ; other families for 
each of the electro-positive metals ; others for each of the bases 
of earths and alkalies. Each of these families was subdi¬ 
vided according to the electro-negative elements. Thus, Cop¬ 
per had the subdivisions,—1. Pure Copper; 2. Sulphurets of 
Copper, of which there are nine or ten (including mixtures of 
V. Genus Copper Pyrites. 
Tessular or Pyramidal. 
Colour brass-yellow, copper-red. 
H = 3-0 to 4-0. 
G = 4-1 to 51. 
I. Species Octoliedral Copper Pyrites. 
Tessular. 
Cleavage, octohedron very indistinct. 
Colour copper-red. 
H = 3 0; G = 4-9 to 5-1. 
