Find the centre of the bottom, and through it scratch plainly four
diameters 45 degrees apart. From their ends draw perpendiculars up the side
of the kettle.
[Illustration: FIG. 96 (a).]
Now draw on a piece of paper a section of the kettle, and from what is
selected as a convenient water-level run a line obliquely, at an angle of
45 degrees, from the side to the bottom. Measuring off from this diagram,
you can establish the points in the side and bottom at which the upper and
longer side of the tubes should emerge. Mark these off.
Next bevel off a piece of tubing to an angle of 45 degrees, cutting off
roughly in the first instance and finishing up carefully with a file till
the angle is exact. Solder to the end a piece of tin, and cut and file this
to the precise shape of the elliptical end. Detach by heating, scribe a
line along its longest axis, and attach it by a small countersunk screw to
the end of a convenient handle.
Place this template in turn on each of the eight radii, its long axis in
line with it, being careful that the plate is brought up to the marks
mentioned above, and is on the bottom corner side of it.
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