lowing affords. However, even in bending a narrow tube it is
possible to proceed in the wrong way. The wrong way is to heat a
short length of the tube and then bend it rapidly, holding the plane
of the bend horizontal. The right way, per contra, is to use a
batswing burner to heat, say, two inches of the tube with constant
turning till it is very soft, and then, holding the glass so that the
bend will be in a vertical plane passing through one eye (the other
being shut), to make the bend rather slowly.

If an exact angle is required, it is as well to have it drawn out on a
sheet of asbestos board. In this case bend the glass as described
till it is approximately right, and finish by laying it on the
asbestos board and bringing it up to the marks. A suitable bit of
wood may be substituted for the asbestos on occasion.

N.B: The laboratory table is not a suitable piece of wood. A
right-angled bend is often wanted. In this case the corner of a table
will serve as a good guide to the eye, the glass being finished by
being held just above it. If great accuracy is wanted, make a wooden
template and suspend it by a screw from the side of the table, so that
the vertex of the gauge for the interior angle projects downwards,
then finish by bending the tube round it. The wood may be about half
an inch thick.

If a sharp bend is required, heat the tube in the blow-pipe, and bend
it rapidly, blowing out the glass meanwhile. The reason why a long
bend should be held in a vertical plane is that the hot part tends to
droop out of the plane of the bend if the latter be made in a
horizontal position. To bend a tube above half an inch in diameter is
a more or less difficult operation, and one which increases in
difficulty as the diameter of the tube increases.

A U-tube, for instance, may be made as follows: Use the four
blow-pipe arrangement so as to heat a fair length of tube, and get,
say, two inches of tube very hot--almost fluid, in fact--by means of
the carbon block supported from a stand. Remove the tube rapidly from
the flame and draw the hot part out to, say, three inches. Then,
holding the tube so as to make the bend in a vertical plane, bend it
and blow it out together to its proper size.

This operation seems to present no difficulties to experienced
glass-workers, even with tubes of about one inch in diameter, but to
the amateur it is very difficult. I always look on a large U-tube
with feelings of envy a