EMICAL NEWS . ; ; ; ;
Comets Ban) Combination Blowpipe for Glass-Working. 253
4 I ”
brass tube ¢ and d carry the air jets, the one for the blast
being about 5 m.m., and that for the small 1 to I} mm.
diameter. These sliding tubes are necessary in order to
adjust the distance of the jets from the end of the tubes
of which they form the centre, the form of the flame gbtained
 being greatly dependent upon this adjustment.
The jets are supplied with air from foot bellows through
che india-rubber tubes g and 4. In the interior of the
support (i) for the large tube b, is turned a groove, into
which the small brass pipe, 7, conduéts air from the bellows
through the india-rubber tube, 2. The rate at which the
air is forced into the tube 4 from the groove, is regulated
once for all by screwing b into its support (i) until it
nearly meets the other part of the tube, which is
screwed in from the opposite side, thus forming a
narrow slit, through which the air is admitted equally all
round (see Fig. 2) Mixing the air with the gas in this

THE CHEMICAL NEWS.

AT the present advanced stage of chemical and physical
‘nquiry, when so much depends upon the construction of
original apparatus, into the composition of which no
material enters so largely as glass, it is impossible to
over-estimate the value; to workers in almost all branches
of science, of even a slight proficiency in the art of
manipulating that substance in the blowpipe flame.
In the course of my experience in experimental science
[ have frequently met with difficulties}in the construétion
of originally designed glass instruments, which have
necessitated improvements in the ordinary glass-blowing
apparatus, in order to properly overcome them. Such
experiences have led me to devise, and from time to time
‘mprove, a blowpipe for myself, with which I may safely
say anything in the way of glass work within the limits
of possibility may be done with far greater ease than with
any ordinary blowpipe.
The description and woodcut given below, taken
from the instrument that has assisted me so much in
carrying out the experiments in Mr. Crookes's later researches,
 with which I have had the honour of being so
closely associated, will, I trust, be of service to those who
wish to be able to constru& for themselves small pieces of
originally-designed glass work, which are so difficult to
obtain from the instrument maker, and which the ordinary
workman seems incapable of comprehending.
Fig. I.

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=

SECTION,
zp and b are the two parts of the tube b, Fig. 1. d, the support
Fig. 1. ¢, the groove into which the air is conducted by the
little pipe j, Fig. 1. e¢, the circular slit formed by a and b,
nearly meeting in the centre of the groove.

manner causes its complete combustion at the mouth of
the tube, the flame issuing similarly to that from a very
iarge Bunsen burner, but much broader. The india-rubber
pipe, I, which comes up through a hole in the bench, supplies
 the gas from the main,
The whole instrument is supported from the bench on
some kind of universal joint, which enables the operator
to dire his flame in any direction he pleases. The best
arrangement for this purpose consists of two brass balls
about §"” diameter, one attached to the instrument, the
other screwed into the bench. These two balls are
clamped together by two pieces of brass or iron, m and =,
through which passes a thumb-screw, 0. © This forms a
joint which will allow the blowpipe to be placed in almost
any position, and is capable of far more motion than the
ordinary ball and socket, at the same time being very
simple and easy of construction.

£76 . 3.

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pr

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TT

a and b are two brass tubes, 3” and §' in diameter
respectively, a being used for the produdion of the small
pointed blowpipe flame, and & for the large flame or blast.
Gas is supplied to these two tubes separately by the taps
¢ and f, both of which have long lever handles projecting
out to the right of the instrument. I may here mention
that these lever handles to the taps are very necessary
when rapidity is required in turning the gas on or off, as
2 knock with the finger vp or down is then generally
wfficient for the purpose. The inner sliding pieces of

The air from the bellows is divided by a three-way
siece, {, from which india-rubber pipes, &, g, and #, pro.
ceed to the different parts of the blowpipe, These three
india-rubber pipes which pass the bench in little nicks
‘Fig. 3, a) cut in its edge, are kept in their places by pieces
of brass screwed over them, The passage of the air ig
stopped by simply kinking the india-rubber tubes, which
8 quite sufficient for the purpose, and to 8 great extent