ch gears with a screw which rides
loosely upon the mandrel, and is kept from rotating by a finger on the
headstock. This center, in its rotation, carries with it the ball,
which is thus slowly moved round an axis parallel to the face plate,
at the same time that it revolves about the axis of the mandrel, the
result being that the tool cuts upon the ball a scroll, of which each
convolution is approximately a circle, and lies in a plane parallel to
the line of centers.

When the chuck is set for one size of ball, which may be done in a few
minutes, any quantity of that diameter may be turned without further
adjustment. A roughing cut for a 2 in. ball may be done in one minute,
and a finishing cut leaving the ball quite bright in the same time.
The two paps are cut off within one-sixteenth of an inch and then
broken off, and the ball finished in the usual way. On account of the
work being geometrically true, the finishing by the ferrule tool is
done in one quarter of the time usually required.

[Illustration: IMPROVED BALL TURNING MACHINE.]

The chuck may be applied to an ordinary lathe or may be combined with
a special machine tool, as show in our illustration. In the latter
case everything is arranged in the most handy way for rapid working,
and six brass balls of 2 in. in diameter can be turned and finished in
an hour. The machine is specially adapted for turning ball valves for
pumps, pulsometers, and the like, and in the larger sizes for turning
governor balls and spherical nuts for armor plates, and is
manufactured by Messrs. Wilkinson and Lister, of Bradford Road Iron
Works, Keighley.--_Engineering._

* * * * *

COOLING APPARATUS FOR INJECTION WATER.

It often happens in towns and where manufactories are crowded
together, that the supply of water for condensing purposes is very
small, and consequently that it attains an inconveniently high
temperature under unfavorable conditions of weather, resulting in the
deterioration of the vacuum and a consequent increase in the
consumption of fuel. To remedy or to diminish this difficulty, Messrs.
Boase and Miller, of London, have brought out the water cooler
illustrated above. This consists, says _Engineering_, of a revolving
basket of wire gauze surrounding an inner stationary vessel pierced
with numerous small holes, through which the heated water discharged
by the air pump finds its way into the basket, to be thrown out in the