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Feather-Shot Copper

Melted copper, poured in a small stream into cold water. It forms small pieces, with a feathered edge, hence the name. It is used to make solution of copper. 3241. Test for the Quantity of Copper in a Compound. The quantity of copper 3250. Welding Copper. A compound present in any compound may be estimated of 358 parts phosphate of soda and 124 parts boracic acid is prepared, and is used when the by throwing it down from its solution by pure LEAD. metal is at a dull red heat; the heat is then metal. When, however, leaden cisterns have increased till the metal becomes of a cherry iron or zinc fastenings or braces, a galvanic red color , and the latter is at once hammered. action is set up, the preservative power of A hammer of wood is recommended for this saline matter ceases, and the water speedily purpose, as the metal is liable to soften at a becomes contaminated with lead. Water conhigh heat; and the hammer should be used All scale and carbonaceous matter must be removed from the surface of the copper, as the success of the welding depends on the formation of an easily fusible phosphate of copper, which would be reduced to a phosphide by the presence of carbon. 3251. To Prevent the Corrosion of Copper and Other Metals. The best means of preventing corrosion of metals is to dip the articles first into a very dilute nitric acid, immerse them afterwards in linseed oil, taining free carbonic acid also acts on lead; and this is the reason why the water of some springs, kept in leaden cisterns, or raised by leaden ties. Free carbonic acid is evolved during the en pumps, possesses unwholesome properfermentation or decay of vegetable matter, leaves of trees falling into water-cisterns and hence the propriety of preventing the formed of lead.

Ores. Lead ores, or galena, may be tested in 3255. To Test the Richness of Lead different ways. The wet way is as follows: and allow the excess of oil to drain off. By Digest 100 grains of the ore in sufficient nitric this process metals are effectually prevented acid diluted with a little water, apply heat to from rust or oxidation. expel any excess of acid, and largely dilute Next