Marine biology -- Great Britain; Seashore; Seashore biology
The writer has preserved many hundreds of small marine and other objects
in glass tubes of dilute spirit that have been hermetically sealed, thus
rendering the slightest loss absolutely impossible, while the perfect
exclusion of air prevents the development of fungoid growths that
sometimes make their appearance in imperfectly preserved specimens. The
making and closing of such tubes, though a more or less difficult
operation at first to those who have had no previous experience in
glass-working, become exceedingly simple after a little practice; and
believing it probable that many of our readers would like to try their
hand at this most perfect method of preserving and protecting small
objects, we will give a description of the manner in which it is done.
The apparatus and materials required for this work are:--Lengths of
‘soft’ glass tubing, varying from about one quarter to a little over
half an inch in internal diameter; a supply of diluted spirit--about
half spirit and half water; a Herapath blowpipe, preferably with
foot-bellows; and a small triangular file.
The glass tubing may be cut into convenient lengths by giving a single
sharp stroke with the file, and then pulling it apart with, at the same
time, a slight bending _from_ the cut made.
[Illustration: FIG. 41.--SHOWING THE DIFFERENT STAGES IN THE MAKING OF
A SMALL SPECIMEN TUBE]
Cut a piece of tubing about eight or nine inches long, heat it in the
blowpipe flame, turning it round and round all the time, until it is
quite soft, then remove it from the flame and immediately pull it out
_slowly_ until the diameter in the middle is reduced to about a
sixteenth of an inch (fig. 41, 2). Make a slight scratch with the file
at the narrowest part, and divide the tube at this point (fig. 41, 3).
Now heat one of these pieces of tubing as before just at the point where
the diameter of the drawn part begins to decrease; and, when very soft,
pull it out rather quickly while it is _still in the flame_. The part
pulled now becomes completely separated, and the tube is closed, but
pointed. Continue to heat the closed end, directing the flame to the
point rather than to the sides, until the melted glass forms a rather
thick and flattened end; and then, immediately on removing it from the
flame, blow gently into the open end until the melted glass is nicely
rounded like the bottom of a test-tube (fig. 41, 4). When the tube is
cold, the specimen that it is to contain, and which has already been
stored for a time in dilute spirit, is dropped into it. The tube is now
heated about an inch above the top of the specimen, drawn out as shown
in fig. 41, 5, and again allowed to cool. When cold, the fresh spirit is
poured into the open end of the tube, but the middle part is so narrow
that the spirit will not run down freely. If, however, suction be
applied to the open end, air from the bottom will bubble through the
spirit, and then, on the cessation of the suction, the spirit will pass
Public-domain text, read in full here on John Shaqi.
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