260 
Thoughts on Miner alogical Systems. 
[Sept, 
ness. For, as the observing reader knows, every true analytical arrangement must 
be formed in this way, however disguised. Thus, if we know the specific gravity of 
a mineral, we ask ourselves is it below or above 2-5 ; if the former, is its hardness 
below or above 3-5 ; if the former, is it combustible or incombustible ; if the latter, 
is it sapid or no ; and so on. Perhaps there is an exception in the case of an arrange- 
ment founded like that of Linnaeus, on numbers increasing by unity and with no in- 
termediary determinations. 
21. To show how little there is of certainty or reality in these fancied classes and 
orders, 1 would only refer the leader to the work of Mohs, the best certainly that has 
yet appeared. His orders are completely indefinite ; so many conditions are attached 
to each, notwithstanding the small number of species which it may contain ; and so 
arbitrary and unconnected are these conditions, that it is perfectly impossible to 
conceive any thing like a clear idea of the character of tbe order. In reality they 
are rather lists of species than real abstractions. Tbe use of a classification, at least 
of an analytical one is, if it have any nse at all, to assemble species together, that 
have the characterising property or properties in common But to congregate hetero- 
geneous bodies, each of which requires a condition or modification of the character 
to admit it ; this is any thing hut generalisation. We see, for instance, in the order 
Halolde, that to admit Gypsum two conditions are necessary. 
22. Though X do not recognise the existence in nature of any such distinctions as 
classes or orders, yet I find in following out my table that certain groupes of species 
present themselves, the members of which seem in some measure allied to each other. 
These may be called sections, and I have for reference distinguished them by names. 
It must not, however, be supposed that I consider these, groupes as coordinate or 
even natural ; they are merely intended to form a step in the analysis on which we 
may rest, and thus avoid the confusion of so extensive a table as must be required 
to include all the known species. Each of these groupes or sections will become 
the subject of a separate table, which I may communicate on a future occasion. 
At present, having swelled this paper beyond its intended limits, I shall content 
myself with giving the fundamental table. Note, it has been found convenient 
to combine the two characters of specific gravity and hardness into a joint one, 
by which is meant that a mineral should have a certain hardness with a certain spe- 
cific gravity. In this way, very natural as well as analytical groupes are formed. 
The shortest and most intelligible way of expressing this condition is by giving in 
numbers the value of the ratio between them : thus G -j- H — less than 6 — 10 or ,6 
means that if the specific gravity be, say, 4 then the hardness must be above 6,6 
because 4,0 -r- 6,6— .6 such a character excludes any mineral having a lower hard- 
ness, whatever its specific gravity. The figures in the last column show the num- 
ber of species in each gvoupe. 
1. A specific gra- 
vity below 2,5 „ 
*C 
ei 
£ 
o 
i§ 
£■ 
<3 
J- 
fco 
AP 
’« 
Ci, 
es 
< 
r C 
Specific 
gravity 
less than j 
4,4. 
Every Mineral has 
( Combustible,- — ~ 1 Combustible 11 
f Soluble in wa- 
Incombustible < ter, 2 
L Insoluble, — — 3 
Hardness above 3,5 -.- .. ftfr . rri .. rjrisirr „ 4 
rG 
Hardness 
above 4,5 
insoluble 
j in acids,-. 
jj less than ,6, . 
Salt, 17 
Koupholite*,ll 
Zeolite,™™ 22 
Gem,™™™. 32 
H more than, 6- 
[Hardness below 4,5 soluble in acids, ™ 
Specific gravity more than 4,4 
Sp. Gr. less 
than 3,3 6 
Sp. Gr. more 
than, 3,3 7 
d 
9 
Streak colour- 
fOull 
[ Metallic, , 
Schorlf,™. 24 
Spar, 13 
Haloide 20 
_ Baryte,, 19 
One ofthepris- 
maticcolours.lO Chromate?, 20 
Brown or black 
or .dirty red. XI Ore,... 12 
With metallic lustre,. 12 Glance, , 30 
13 Metal, 14 
Without me- 
tallic lustre in 
substance, 
* From Kovfoc light, and Xlfloc a stone. M. 
+ There is an objection to the use of this term, which is the name of a mineral. 
£ From ctXg suit , and zifiog appearance, 
§ From colour. This ten- ' ojectioaable, having a different sense ia che- 
mistry* 
