ways, applied wet; the
lubricant generally recommended is stale beer, but this may be
replaced by water containing a small quantity of glue, or any other
form of gelatine in solution--a mere trace (say .1 per cent) is quite
sufficient. Very fair results may be got by using either pure or
soapy water. The rotating brushes require to be mounted on a lathe,
and may be run at the same speed as would be employed for turning
wooden objects of the same dimensions.

Since the brush has to be kept wet by allowing water or its equivalent
to drip upon it, it is usual to make a tin trough over which the brush
can revolve, and to further protect this by a tin hood to keep the
liquid from being thrown all over the room. In many works the brush
is arranged to lie partly in the liquid, and this does very well if
the hood is effective.

There is a superstition that electro-deposits stick better to
scratch-brushed surfaces than to surfaces which have not been so
treated, and consequently it is usual to scratch-brush surfaces before
electro-deposit. However this may be, there is no doubt that
adherence and solidity are promoted by frequent scratch-brushing
during the process of depositing metal, especially when the latter
tends to come down in a spongy manner.

Gilt surfaces--if the gilding is at all heavy--are generally dull
yellow, or even brown, when they come from the bath, and require the
scratch brush to cause the gold to brighten, an office which it
performs in a quite striking manner. The same remark applies to
silvered surfaces, which generally leave the bath a dead white--at
all events if the deposit is thick, and if ordinary solutions are
employed. In either case the touch of the scratch brush is magical.

Sec. 131. Burnishing.

Burnishers of steel, agate, or bloodstone can be bought at the shops
where scratch brushes are sold, and are used to produce the same
brightening effect as can be got by scratch-brushing. The same
solutions are employed, but rather stronger, and the burnisher is
swept over the surface so as to compress the deposited metal.
Burnishing is rather an art, but when well done gives a harder and
more brilliant (because smoother) surface than the scratch brush. On
the whole, steel burnishers are the most convenient if in constant
use.

If the burnishing tools have to lie about, steel is apt to rust,
unless carefully protected by being plunged in quicklime or thickly
smeared with vaseline, and