Messrs. Gressel and Redwood, of London, recently patented the following methods of coating iron with zinc and other metals. To COAT IRON WITH ZINC.—The zinc is ' melted in an open vessel, and on its surface is placed a layer of the chloride ot zinc, or a mixture of equal parts of chloride of zinc and chloride of potassium, in the proportion of eight of the former and two of the latter. ' When the salt is in a state of fusion, the metal to be coated is placed in the bath, and allowed to remain there till a coating of sufficient thickness has been obtained; it is then withdrawn, and any parts of its surface im-1 perfectly covered are sprinkled with sal ammoniac, and the sheet of iron again immersed in the bath. To COAT IRON WITH SILVER.—The metal must be first amalgamated with mercury by the following process ; 12 parts of mercury, 1 of zinc, 2 of sulphate ot iron, 2 of muriatic acid, and 12 of water are mixed together, and heated in an open vessel to about 200 Fah. ; the iron is then immersed, and the mercury rubbed on its surfaces until amalgamation is effected. The silver or alloy is to be melted in a crucible, and the amalgamated iron placed therein, when a coating of silver or alloy will be deposited. To COAT IRON WITH COPPER OR BRASS.— The copper or other coating is to be melted in a suitable vessel, and a stratum of borosili-cate of lead placed on its surface ; the iron is then to be plunged into the molten metal, and retained there until a coating is deposited on it. Iron coated with the tin or lead may be treated in a similar manner. Another method of coating iron with copper is to place in a crucible a quantity of chloride of copper, upon which is laid the iron to be coated, and over that a quantity of charcoal. The crucible is then submitted to a red heat and the chloride of copper fused, and a coating of copper deposited on the iron. Or the vapor of chloride of copper may be employed for the same purpose. The coating of copper thus obtained, may be converted to one of brass by exposing the sheet of metal to the vapor of zinc in a closed vessel.