Vermont phÅ“nix. [volume] (Brattleboro, Vt.) 1834-1955, 1881-01-21
MATTER.
or Crystals.
No. IL.

and resemblance to artificial workmanship.
In this branch Of mineralogy the admirer of
natures laws and the lover of the beautiful
can meet the former to behold the effect Of
one or more of the inherent, occult forces Of
matter that have, with their co-workers, made
the earth and the universe what they are I;
the latter to admire the skilful workmanship
of the natural artizan, rivalling often excel
ling, the ideal of the critical devotee Of
aesthetics Here, as elsewhere, it is humili
ating that effects cannot always be traced to
their cause or, if the immediate cause is
discovered, that the elements of the cause
and their subtitle movements towards the ac-
complishment Of the given purpose are mex
plicable and unseen. Moreover, when the
immediate cause is discovered, this is found
to be the effect Of an anterior cause, and this
anterior cause the effect of a cause still more
remote, until the investigator finds himself
pursuing an endless chain Of phenomenal in
quiry, allurng him onward as new links are
discovered, and the conservation of law and
order becomes more and more manifest. But
to the subject.
1t is a well known fact that minerals in
|
that is to say each mineral assumes its char
acteristic form by which the practical crys-
photographer is generally able to decide what
mineral is before him unasssted by its other
characteristics. Yet each specimen is not al
ways true TO its predominant form most
species are subject to what mineralogists call
modified forms, which means departure in
some respects from the predominant form,
yet retaining so much of it as to lead to its
identity.
The crystalline forms (Which must gener-
ally be omitted on account of their great
number) are reduced to seven predominant
ones, viz. the prism, heIahedron, pyramid,
lens dodecahedron, table and icosahedron, to
which all the modified forms may be traced.
The predominant form of quartz crystal is
the six-sided prism of equal lateral planes,
terminated at one or both ends with a six
sided pyramid with a horizontal base, each
terminal plane forming an isosceles triangle.
But the predominant form is often modified
into prism of unequal lateral planes, two
opposite sides being broadened at the ex-
pense Of the other sides yet the crystal re-
tains so much of its predominant form that
its identity is not lost. The prism is Of no
definite length, and it is sometimes wanting
entirely then the crystal is a double six
sided pyramid, or dodecahedron.
1t is a remarkable fact that the angles Of
crystals of the same variety never vary in
whatever part of the world they may be
found aud this constancy of angular meas
urement is one of the surest means of dis
tinguishing them For instance: The angle
of quartz crystals formed by the union Of the
lateral with the terminal planes, is l4l2 40,
and no difference is discovered in different
specimens. The angle formed by the two
opposite terminal planes of the pyramid is
| - % and also never varies. That variety
of carbonate of lime known as calcareous
spar forms angles in cystallizing of 1915 8
and 747 90. In quartz, the base of the
pyramid, in predominant forms, is a
plane, and rests upon the plane end Of the
prism in calcareous spar the base of each
terminal plane is oblique, the obliquity
changing with each alternate plane Hence,
instead of pyramid with plane base as in
quartz each terminal plane is converted into
a scalene triangle, and the pyramid rests up
on prism whose end is similarly formed.
Basaltic columns found in Europe, and to
some extent in the United States, though de-
MED by some theorists to be analogous to
crystals are, nevertheless, objects of much
interest as showing the vast resources of ma
ture in the conversion Of matter, and almost
inducing the belief that she bad in view the
degradation of art. These columns have
from three 10 twelve sides generally from
| five to seyen-are not surmounted with pyra-
miis, but are in joints, with nicely fitting
concave and convex ends The pillars of the
famed Giants Causeway' in Ireland are 30
nicely fitted together at their sides and ends
that knife blade cannot be inserted be-
tween them, and yet are completely separate
and can be lifted out of their places.
Many years ago geologists became interest
cd to ascertain the agency that had caused
these rocks to assume the columnar form.
Mr.. Gregory Watt believing in their igneous
origin, conceived the idea OF initiating ma
ture upon small SCALE and in 1904 melted
700 lbs. of the rock, and observed closely the
changes that took place within the mass in
cooling. The interior, which cooled slowly,
at first formed itself into great number of
spheres, then pressing laterally upon each
other they formed themselves into prisms
with concave and convex ends as they are
found in their natural position. Thus the
| igneous, if not the crystalline origin of ba-
saltic columns was established.
Everybody has noticed the capitalization
of water upon window -panes but it is
doubtful if many, comparatively, have OBJ
served their fanciful, unique figures, or know
that they are formed in obedience to law as
rigid as are the crystals of quartz or fiuate of
lime. A common figure consists of rods
sometimes parallel and straight; at other
times curved, radiating from a central point,
basal ends truncated and furnished with
spcules upon either side. These rods some
times cross each other at every possible an
gle, forming a plexus or network, and are
never destitute of the inevitable spicule
Another form would, at first view, be called
stelliform but it proves to be fern-like. Un-
der the microscope these tiny figures are
brought into relief and extraordinary beauty
several stems-geneTally from four TO six
being joined, sometimes sending out perpen-
| pendicular veins, at others the stem and the
vein form acute or obtuse angles. Under a
favorable condition of light nothing can eI-
ceed the exquisite loVeliness of these crys-
tails. Imagine figures of the purest silver in
every possible position, some edged with the
golden hues of sunset cloud, others with the
inimitable cerulean blue, colors appearing
and fading away like phantoms as the instru-
ment or the eye changes position and faint
idea may be formed of a common exhibition
of rare beauty that Hogarth or a Raphael
might attempt to initiate, but without sue
cess. Under different circumstances single
ferns several inches long, gracefully turned,
may be seen imitation of extinct flora, fan
shaped, overlapping one another, emerging
| from nnnIrnI r,ninh or