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A patent has recently been taken out in England by Mr. Arthur Wall, of London, for a combination of metals possessing different electric characters for the sheathing of ships. The alloy is made by melting two and a half parts of copper in one crucible ; in another nine parts of zinc, eighty-seven of lead, one part of mercury, and a half a part of bismuth; then mixing the contents of both crucibles, covering the surface with charcoal dust, and stirring well until all are incorporated. It is stated that the mercury in this alloy protects both the zinc and copper from the action of sea water. The contents of the crucible are run into ingots, and rolled into sheets. The same inventor has also obtained a patent for protecting the bottoms of iron ships from the action of sea water, by the use of a composition of litharge made into a smooth thin paste with turpentine, to which is added an equal weight of resin. The whole is then put into a close iron vessel placed over a fire, naphtha added through an aperture in the lid from time to time, and the boiling kept up slowly for about two days, until the whole has assumera tenacious adhesive character and a creamy consistency. It is then fit to be applied to the iron of the vessel as a primary coating. A second coating is given to the iron with a composition of resin, combined with one-fifth of its weight of an oxyd of mercury and powdered charcoal mixed in turpentine. This outer coating fills up all cracks or gaps left in the first application, and the nature of the composition is stated to be such that it prevents barnacles adhering to the jtron, and resists the corroding action of salt water. The protection of the bottom of iron ships is a matter of great consequence in Great Britain where there are so many built, but is not of so much importance here at present, yet it is of some consequence to us also, as we have a few iron vessels, and the probability is that their number will always keep increasing.
