108 Prof. Weiss on the Methodical and Natural Distribution 
ral cases. I called it then, when taken together, Viergliedrig 
or the Quaternary System , an expression which I now restrict 
rather to the homoedral subdivision which comprehends the 
systems such as Zircon , Idocrase , &c. But there is reason now 
to admit, that there are not only bino-nniaxal hemiedral sys- 
tems, but also others, in a double sense, analogous to the pyrito- 
edral and tetra-edral systems, which I shall call, the one Bi- 
noquaternary (vier-und-zweig liedrig) , such as Harmotome ap- 
peared to me to be, and perhaps a part of Bournonite, and the 
other Quaterno-tetraedral ( tetraedrisch viergliedrig) , to which 
I would refer not only Copper pyrites, after the observation of 
M. Mohs, but also Sulphate of Magnesia, of which I have crys- 
tals too well marked to allow it to be doubted that they belong 
to this class. 
If the measures of the angles of Wolfram, are such as they 
are at present given, this system will form a separate subdivision, 
which we may call quaternary tetarto-edral, or rather quaternary 
hemi-et-tetarto-edral, and which will be analogous to that which 
is found among the systems belonging to the third general case. 
It is a long time since I have described it thus; and as I call 
vter-und-zweigliedrig the system of Harmotome, I shall call 
this vier-zwei-und-eingliedrig, or bino-singulo-quaternary, con- 
formably to the other representative terms which I have adopt- 
ed. 
The third general division is formed by systems with three 
axes perpendicular to one another, but all unequal. I call 
these systems singulaxia ( ein-und-einaxig ). I have subdivided 
this vast division, according as the systems comprehended in it 
were homoedral or hemiedral, into binary systems, ( zwei-und - 
zweigliedrig) sy sterna binarium , such as Topaz, Sulphate of 
Barytes, her, then into bino-unitary systems, ( zwei-und-einglied- 
rig, sy sterna bmo-singulaxmm,) such as Felspar, Amphibole , 
Pyroxene, he. ; and, lastly, into unitary systems, ( ein-und-ein- 
gliedrig, sy sterna singulaxium ), such as Axinite and Sulphate of 
Copper. These last containing the fourth, that is, the half of 
the half of an entire number of faces co-ordinate to one another, 
are justly called by their more theoretical name, uni-axal te- 
tarto-edral systems , instead of tetarto-prismatic systems, as they 
are called by M. Mohs. We shall also designate by the more the- 
