64 
Mohs' System of Crystallography 
order, a genus, a species from one or more others, is named a 
character ; and the collection of all those last the system of cha- 
racters^ or characteristic. That collection of marks, by the, know- 
ledge of which we obtain a complete representation of the object, 
is named a description^ The description, and the matters con- 
nected with it, are doubtless of great importance for mineralogy, 
(ii. 56.) ; but the investigation of them -belongs not to this place. 
6. Scias, characterem non constitiiere genus, sed genus cha- 
racterem. Linne, Phil. Bot. § 169. — The system of characters be- 
longing to the natural history system will be estimated in the 
right point of view, by considering that it is not the character 
that determines the order, the genus, the species ; but the order, 
the genus, the species, that determine the character. The justness 
of the settlement of the orders and genera, cannot therefore be 
discovered from the characters, but only from the natural history 
properties of the substances comprised in that determination. 
The system of characters will not, however, be without its use, 
if, by means of it, the individuals can be easily submitted to 
natural historical conceptions. 
7. Difficidty of the system of characters in a natural system 
of Mineralogy. — In artificial systems, the settlement of the cha^ 
racters is attended with no difficulty ; in a natural one with very 
much. In the natural system of mineralogy, these difficulties 
manifest themselves chiefly in what regards the orders. When 
the orders have been collocated in nature, the examination of 
them clearly displays their difference. But on attempting to 
denote these differences by marks, and to express them by words, 
the mineralogist has to strive with an almost boundless multi- 
plicity, which most frequently divests the marks of their univer- 
sality. This renders it necessary, instead of particular marks, 
to employ their mutual relations ; from which arise some pro- 
perties not altogether corresponding to the characters. 
8. No chemical helps to iU — One apparent mode of obviating 
this difficulty is not unknown to me. It is indeed easy to discover 
that the genera and species of the natural history orders, agree 
in certain chemical relations ; and these might have been ad- 
mitted among the characters. The latter would, in this case, 
have been simplified and abbreviated, — and thus have been pro- 
vided with qualities very desirable for them. In the higher steps 
