Evening star. [volume] (Washington, D.C.) 1854-1972, 1907-02-17
MAKING QUARTZ GLASS;
Discovery at the Carnegie
GeophysicaI Laboratory.
IMPORTANT TO THE ARTS
Commercial Possibilities Not Yet
Considered.
DEMAND FOR THE PRODUCT
Feat Achieved by Arthur L. Day and
E. S. Shepherd After Many
Fruitless Attempts.
IMPORTANT TO THE ARTS
Possibilities Not Yet
Considered.
DEMAND FOR THE PRODUCT

One Of the most important commercial
developments from the work Of the Carne-
gle Geophysical Laboratory in Washington
Is the possibility Of manufacturing quartz
glass. DR.. Arthur L. Day and E. s. Shep-
herd are the two gentlemen who have
achieved the feat They do not take any
interest In the commercial possibilities of
the matter. Dr. Day, for instance, says
that they have shown that the thing can be
done, and now If a commercial company
wants to take it up it can DO so, all of the
facts having been made public in the sci
entific press and before learned societies,
so that there is no possibility of any one
getting patent on it.
The value of quartz glass over ordinary
glass Is that it can be heated to tenn
perature of about 1000 degrees c. without
soften1ng, and its expansion under any
ordinary heat is so trifiing to be almost
negligible quantity. 1t also can be heated
almost red hot and plunged into cold
water without cracking and has the pecu-
liar property of allowing the passage Of
ultra violet light rays, making it remark
ably valuable in photography.
The value of quartz glass had been recog-
nized for long time, and owing to the
cheapness of German labor it had been
manufactured in a way for laboratory use
clear quartz crystals and sticking them to-
gether. The tubes and other vessels thus
built up were rough, patchwork looking
affairs, but served a number of useful
purposes. However. there was no way of
manufacturing the substance into glass
sheets of any size because random masses
of broken quarts could not be fused to-
gether without having the resultant glass
full Of air bubbles. Quartz will liquefy
under intense heat. but it will never get
sort enough for the air bubbles OF escape.
The result was that melted quartz was
dirty, porous mass more or less like pum-
ice stone.
The Discovery.
The workers of the Carnegie laboratory
tried all sorts of methods. If the quartz
was intensely heated, free silicon was de-
posted on the inside of the air bubbles
and the glass was spoiled in two ways, in
stead of one, which was a-plenty. The
final solution of the problem was found in
heating the quartz to the melting point
about 1900 degrees Fahrenheit, and then
subjectfng it to an air pressure of between
400 and 500 pounds. After this it was al
lowed to gradually cool. The air pressure
squeezed out the air bubbles, and the re-
suit was solid and clear mass Of quartz
glass. The plates that have so far been
made are only about three by five by half
an inch In size. The bubbles are few, not
over one-half milimeter In diameter, and
are not frequent enough to interfere with
the use of the glass for lenses, mirrors and
other optical work. The experimenters
tHlnh tndt a little more skill and expert
ence would enable them to make the glass
entirely free from flaws.
The value Of the glass in photogra PHO
work is due, as has been said, to its prop.
erty of allowing the passage Of the ultra
violet rays, which are the rays that do the
actual work in photography. In this con-
nection the glass will be peculiarly valuable
for the Cooper-Hewitt incandescent light
tubes, such as are now In use in the post
office building. These tubes are very val
liable now for Photographic work, but with
the quartz glass tubes they will be i'm
mensely more SO.
The glass, when 1t is once made can be
blown or pressed or cut like ordinary glass
1t takes much higher degree Of heat to
handle 1t. the oxyhydrogen blowpipe having
! to be used, while the material has to be
worked much more quickly than ordinary
glass.
Commercial Possibilities.
AS to the cost of the process, DR.. Day
would attempt no estimate, merely saying
that they had spent a great deal of money
In doing as much as they had done, but
that probably if the thing were done on a
| commercial scale and a larger unit of pro-
| duction adopted the cost would be consid-
erably reduced. The cylinder where the
glass is made is a powerful iron "bomb I"
lined with graphite, and one of the prob
lens in working on a larger scale would be
to secure larger sheets of graphite for this
lining. These sheets could be supplied only
by one of the big companies now operating
at Niagara, and would be an expensive in
vestment, but there Is little question that
they could be made, and when the produce
ton Is put on commercial basis the ma
terials for the work doubtless will be forth
coming.