t; but the cream is deflected up outside F into space E, and escapes
through a hole one-sixteenth of an inch in diameter perforating the
plate G. The cream is flung into space K and trickles out of spout B,
while the water flies into space H and trickles away through spout A.

THE "HYDRO.,"

used in laundries for wringing clothes by centrifugal force, has a solid
outer casing and an inner perforated cylindrical cage, revolved at high
speed by a vertical shaft. The wet clothes are placed in the cage, and
the machine is started. The water escapes through the perforations and
runs down the side of the casing to a drain. After a few minutes the
clothes are dry enough for ironing. So great is the centrifugal force
that they are consolidated against the sides of the cage, and care is
needed in their removal.

[35] Inventor of the lathe slide-rest.

[36] Living germs; some varieties the cause of disease.

[37] That is, centre-fleeing force. Water dropped on a spinning top
rushes towards the circumference and is shot off at right angles to a
line drawn from the point of parting to the centre of the top.

Chapter XIX.

HEATING AND LIGHTING.

The hot-water supply--The tank system--The cylinder system--How a
lamp works--Gas and gasworks--Automatic stoking--A gas
governor--The gas meter--Incandescent gas lighting.

HOT-WATER SUPPLY.

A well-equipped house is nowadays expected to contain efficient
apparatus for supplying plenty of hot water at all hours of the day.
There is little romance about the kitchen boiler and the pipes which the
plumber and his satellites have sometimes to inspect and put right, but
the methods of securing a proper circulation of hot water through the
house are sufficiently important and interesting to be noticed in these
pages.

In houses of moderate size the kitchen range does the heating. The two
systems of storing and distributing the heated water most commonly used
are--(1) The _tank_ system; (2) the _cylinder_ system.

THE TANK SYSTEM

is shown diagrammatically in Fig. 192. The boiler is situated at the
back of the range, and when a "damper" is drawn the fire and hot gases
pass under it to a flue leading to the chimney. The almost boiling water
rises to the top of the boiler and thence finds its way up the _flow
pipe_ into the hot-water tank A, displacing the somewhat colder water
there, which descends through the _return pipe_ to the bottom of the
boiler.