covered in contact with the molten metal. The greater part of the
tin is then thrown out and the surface rubbed over with a brush of tow
to equalize the coating; and if not satisfactory the operation must be
repeated. The vessels usually tinned in this manner are of copper and
brass, but with a little care in cleaning and manipulating, iron can
also be satisfactorily tinned by this means. The vessels to be tinned
must always be sufficiently hot to keep the metal contained in them
thoroughly fused. This is covering by contact with melted tin.

The amalgam process is not so much used as it was formerly. It
consists in applying to the clean and dry metallic surface a film of a
pasty amalgam of tin with mercury, and then exposing the surface to
heat, which volatilizes the latter, leaving the tin adhering to the
metal.

The immersion process is the best adapted to coating articles of brass
or copper. When immersed in a hot solution of tin properly prepared
the metal is precipitated upon their surfaces. One of the best
solutions for this purpose is the following:--

Ammonia alum 17-1/4 oz.
Boiling 12-1/2 lb.
Protochloride of tin 1 oz.

The articles to be tinned must be first thoroughly cleansed, and then
kept in the hot solution until properly whitened. A better result will
be obtained by using the following bath, and placing the pieces in
contact with a strip of clean zinc, also immersed:--

Bitartrate of potassium 14 oz.
Soft water 24 "
Protochloride of tin 1 "

It should be boiled for a few minutes before using.

The following is one of the best solutions for plating with tin by the
battery process:--

Potassium pyrophosphate 12 oz.
Protochloride of tin 4-1/2 "
Water 20 "

The anode or feeding-plate used in this bath consists of pure Banca
tin. This plate is joined to the positive (copper or carbon) pole of
the battery, while the work is suspended from a wire connected with
the negative (zinc) pole. A moderately strong battery is required, and
the work is finished by scratch-brushing.

In Weigler's process a bath is prepared by passing washed chlorine gas
into a concentrated aqueous solution of stannous chloride to
saturation, and expelling excess of gas by warming the solution, which
is then diluted with about ten volumes of water, and filtered, if
necessary. The articles to be