MIN 
MIN 
the compact, the latter has been termed 
the jointed fracture; and each is subdivided 
into a number of varieties. Minerals are 
likewise discriminated by their hardness. 
The degree of it in a fossil is judged of with 
most certainty by the comparative facility 
or difficulty of impressing it. Four degrees 
of it are marked by Werner; the “ hard,” 
in which the substance is not capable of be- 
ing scratched by the knife, but gives sparks 
when struck by the steel ; “ semi hard,” when 
it does not strike fire with steel, and may be 
scraped by the knife ; “ soft,” when it may 
be easily scraped with the knife, but receives 
no impression from the nail; and “ very 
soft,” when it is scratched by the nail. 
Hauy determines the degrees of hardness 
according as one fossil impresses another. 
In one division, those are placed which 
scratch quartz ; the individuals belonging 
to this are arranged as much as possible in 
the order of their relative hardness, so that 
when placed in a column, each will impress 
those beneath it. The second class are 
those which will scratch glass : these are ar- 
ranged in a similar manner. In a third, 
those which scratch calcareous spar ; and 
in a fourth, those which make no impres- 
sion upon it. 
Tenacity is that property which relates 
to the cohesion of the integrant particles of 
solid minerals, which, existing in different 
degrees, gives rise to the distinctions of 
brittle, malleable, and the intermediate de- 
gree of sectile. 
The ffangibility denotes the facility with 
which a mineral may be breken. It exists 
in different degrees, which are marked by 
the common terms of difficulty frangible, 
easily frangible, &c. According to the 
AFernerian system, the specific gravity is 
thus described : a mineral is said to be “ su- 
pernatent,” which is lighter than water, and 
will swim upon its surface: it is called 
“ light,” when the specific gravity is be- 
tween 1.0 and 2.0 : “ rather heavy,” when 
the specific gravity is between 2.0 and 4.0 : 
“ heavy,” where it varies from 4.0 to 6.0 : 
and “ very heavy,” when the specific gra- 
vity is above 6.0. The better way is that 
which we have adopted under the several 
genera, of stating the numbers denoting the 
real specific gravity, as found by the hydro- 
static balance. To these external charac- 
ters are added others of less importance, 
which are derived from properties peculiar 
to a few minerals, such as that of adhering 
to the tongue, soiling the finger, feeling 
hard or unctuous, giving a particular streak 
on paper, giving when struck a peculiar 
sound, feeling cold when applied to the 
tongue, having taste, or emitting some per- 
ceptible odour. 
AFith respect to the chemical characters : 
“ fusibility ” is generally determined by the 
action of the blow-pipe, as we can thus ope- 
rate on a small fragment, and perceive ea- 
sily the appearances presented on fusion. 
Some minerals are perfectly infusible by it ; 
others melt with facility ; some fuse with 
intumescence ; others decrepitate or exfo- 
liate when urged by the flame, or lose their 
colour ; in some the fusion is partial ; some- 
times the result is a kind of scoria ; in many 
cases it is a complete vitreous globule, 
transparent or opaque, and of various co- 
lours. These appearances are diversified, 
by adding to the substances various fluxes, 
as borax, and the phosphates of soda and 
ammonia. The action of acids affords ano- 
ther chemical character of fossils, by ob- 
serving whether they eflFervesce w'hen 
touched with the acid, or whether, when a 
small fragment is immersed in it, it is par- 
tially or entirely dissolved ; if the solution 
is fluid or gelatinous ; and what appeaiances 
it presents from the action of re agents- 
Diluted nitric acid is generally used in these 
trials. 'J'o the characters taken from cer- 
tain physical properties are referred the 
phosphorescence, electricity, and magne- 
tism of minerals. Phosphorescence is pe- 
culiar to some minerals, and is therefore a 
property well adapted to assist in their dis- 
crimination. In some it is excited by at- 
trition, more or less strong ; in others, by ex- 
posing them to heat. The electrical state, ei- 
ther positive or negative, is excited in some 
minerals by friction in others by heat ; and 
iron, in many states of combination, is dis- 
covered by its magnetic power. An advan- 
tage is sometimes taken of what are deno- 
minated empirical characters; of these- the 
most important is that derived from the na- 
tural association of minerals; some being 
found in the same situation, and even blend- 
ed with each other ; while there are others 
which have never been observed to occur 
together. 
MINE.S. Gold and silver mines belong 
to the king by his prerogative. By statute 
1 and 5 AFilliam, c. 30, and 6, no mine of 
copper, tin, iron, or lead shall be deemed a 
royal mine, notwithstanding gold or silver 
may be extracted from them in any quanti- 
ties. But the king may take the ore at a 
certain rate, except in Devon and Corn- 
wall. Maliciously to set fire to a mine ov 
