articles due
to hot galvanizing:--

+--------------------------+--------------------------+-------------+
| Description of | Weight of Zinc | Percentage |
| Article | per Square foot | of Increase |
| | | of Weight |
+--------------------------+--------------------------+-------------+
| Thin sheet-iron | 1.196 oz. | 18.2 |
| 5/16-in. plates | 1.76 " | 2.0 |
| 4-in. cut nails | 2.19 " | 6.72 |
| 7/8-in. die bolt and nut | approximately 1.206 oz. | 1.00 |
+--------------------------+--------------------------+-------------+

Tin is often added to the hot bath for the purpose of obtaining a
smoother surface and larger facets, but it is found to shorten the
life of the protective coating very considerably.

A portion of a zinc coating applied by the hot process was found to be
very brittle, breaking when attempts were made to bend it; the average
thickness of the coating was .015 inch. An analysis gave the following
result: tin, 2.20; iron, 3.78; arsenic, a trace; zinc (by difference),
94.02. A small quantity of iron is dissolved from all the articles
placed in the molten zinc bath, and a dross is formed amounting in
many cases to 25 per cent of the whole amount of zinc used. The
zinc-iron alloy is very brittle, and contains by analysis 6 per cent
of iron, and is used to cast small art ornaments from. A hot
galvanizing plant, having a bath capacity of 10 feet by 4 feet by
4-1/2 feet outside dimensions, and about 1 inch in thickness, will
hold 28 tons of zinc. With equal amounts of zinc per unit of area, the
zinc coating put on by the cold process is more resistant to the
corroding action of a saturated solution of copper sulphate than is
the case with steel coated by the ordinary hot galvanizing process;
or, to put it in another form, articles coated by the cold process
should have an equally long life under the same conditions of exposure
that hot galvanized articles are exposed to, and with less zinc than
would be necessary in the ordinary hot process. The hardness of a zinc
surface is a matter of some importance. With this object in view
aluminium has been added from a separate crucible to the molten zinc
at the moment of dipping the article to be zinced, so as to form a
compound surface of zin