The Columbian. [volume] (Bloomsburg, Pa.) 1866-1910, 1907-10-31
MUCH MORE MICA USED.
Once Seen Chiefly In the Stove
Now Employed TO Insulate Wires.

iNOW W
There was a time when mica, or
! isinglass as 1t was far more com
| monty called, was familiar IN one
limited use in every household In
which there was parloi or sitting
room stove, thin, transparent sheets
of this mineral being set in the stove
| door. Through the 'isinglass," not
| destructible when subjected to heat,
as glass would have been, the glow
of the fire within could be seen.
With long use the mica might be-
! come smoked up and Opaque, or 1t
might become marred and bro
ken Then the head of the household
would get and set into the stove
door fresh isinglass, from the stove
dealers, whllc the fragments of the
old were very probably turned over
to the children, who were likely to
be surprised to find into how much
thinner sheets still the thin old
pieces from the stove door could be
divided. AS a matter of fact mica 10
divisibe into sheets one two-thou-
sendth of an inch in thickness.
Now there are many who don't
know mica at all, not even as 1t is
used In stoves, people born and
raised in houses that are heated by
steam, In which no stoves are used
for heating purposes; but while the
number of these is large and all the
time growing, the number of people
who yet use stoves is larger still;
and so while mica may have passed
entirely out OF the sight and mind of
many who once knew It In this use,
and in this use only, the preparation
OF 1t for stove use still constitutes n
regular branch of the mica trade;
and thus one of the old uses of mica
still continues.
Tho chief use to which mica is now
put is one not dreamed of until with
In a comparatively few years, name
ly, as an insulating material in the
construction of electrical apparatus,
for which purpose It's use is now
general and constantly increasing,
and far larger than in any use to
which 1t had ever before been put.
Mica is now used also for making
chlmneys for incandescent gas lamps
placed where they would be exposed
to drafts. or out OF doors, subject TO
the weather. Mica IS used to make
protectors for ornamental candle
shades, and 1t Is used for making
fancy boxes, and. In place of glass,
for covering the labels of drawers,
as In a desk. Ground up mica is now
used In the manufacture of lubri-
cants and of fertilizers, and of dyna-
mite, and in other forms 1t is used
for boiler coverings.
Mica was long used for windows
and for lanterns, and 1t is still used
In lanterns where such use would be
advantageous. 1t Is used In place of
glass In spectacles worn by stone
and metal workers, and in miners
lamps, and 1t has been in the past
or still is put to various other, In
Guiding ornamental, uses; but among
Its various modern uses the chief Is
In It's application to electrical ma
chinery. For this the mica is cut
into hundreds of different shapes
and sizes.
India is the chief source Of the
worlds supply of mica. with Canada
next, the United States next. and
Brazil and other countries following.
Mica, from one source and another
ranges in color from white or trans
parent, through various shades to
black
In the formation In which It ex-
lists It is found in more or less scat
tering deposits. or in pockets. It's
value depends. with regard to the
uses to which 1t may be put. on its
color, It's freedom from impurities
and the size of the sheets that can
be obtained from 1t.
Now this anciently known mineral,
for many years put to varied though
comparatively limited uses. finds
more extensive use than ever In ap-
plications peculiarly modern.