s, benzoline or
petrol blow-lamps and paraffin stoves have become very popular, as they do
away with stoking, and the amount of heat is easily regulated by governing
the fuel supply. Fig. 94 is a sketch of a blow-lamp suitable for the
horizontal boiler shown on pp. 204, and 206, while Fig. 95 shows a
convenient form of paraffin stove with silent "Primus" burner, which may be
used for a horizontal with considerable furnace space or for vertical
boilers. In the case of all these liquid fuel consumers, the amount of heat
developed can be increased by augmenting the number of burners. Where a gas
supply is available its use is to be recommended for small stationary
boilers.

Solid Fuels.--The chief disadvantages attaching to these are smoke and
fumes; but as a solid fuel gives better results than liquid in a large
furnace, it is preferred under certain conditions, one of them being that
steam is not raised in a living room. Charcoal, coke, anthracite coal, and
ordinary coal partly burned are the fuels to use, the fire being started
with a liberal supply of embers from an open fire. Every solid-fuel boiler
should have a steam-blower in the chimney for drawing up the fire; and if a
really fierce blaze is aimed at, the exhaust from the engine should be
utilized for the same purpose.

XIX. QUICK BOILING KETTLES.

[Transcriber's note: Do not use lead solder on articles associated with
human or animal consumption.]

The principles of increasing the area of heating surface in model boilers
may be applied very practically to the common kettle. The quick-boiling
kettle is useful for camping out, for heating the morning tea water of the
very early riser, and for the study "brew," which sometimes has to be made
in a hurry; and, on occasion, it will be so welcome in the kitchen as to
constitute a very useful present to the mistress of the house.

As the putting in of the tubes entails some trouble, it is worth while to
select a good kettle for treatment. Get one that is made of thick tinned
sheet iron (cast-iron articles are unsuitable), or even of copper, if you
are intent on making a handsome gift which will last indefinitely. The
broad shallow kettle is best suited for tubing, as it naturally has a fair
heating surface, and its bottom area gives room for inserting plenty of
tubes. Also, the tubes can be of good length. Let us, therefore, assume
that the kettle will be of at least 8 inches diameter.

In Figs. 96 (a) and 96