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Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1915 Excerpt: ...to the shaft of a small motor or to a belt-driven pulley. When deposition is complete, withdraw the electrodes from the beaker before breaking the current, at the same time washing them off with distilled water to prevent re-solution of the copper. Disconnect the cathode from the circuit, wet it with a little alcohol, dry, and weigh it. From the combined weight of the cathode and copper must be deducted the weight of the cathode. If the copper plate is smooth with a fine metallic luster, it may be dried by burning off the alcohol, without danger of oxidizing the copper. After the copper has been weighed, it is dissolved from the cathode in a little warm nitric acid. LEAD IN ORE MOLYBDATE METHOD Outline. The ore is treated with hydrochloric, nitric, and sulphuric acids and the solution evaporated until the sulphuric acid fumes; water is added to take up soluble sulphates. The lead sulphate with other insoluble matter is filtered from the solution; the lead sulphate is dissolved in ammonium acetate and the lead measured by titrating it with a standard solution of ammonium molybdate. Reagents. Sulphuric acid, dilute (1:1). Sulphuric acid, dilute (1: 10). Ammonium acetate; saturated solution of NH4C2H3O2 in water. Solution of tannin. Dissolve 1 gm. of C14H10O9 in 200 cc. of water. Standard solution of ammonium molybdate. Dissolve 4.3 gms. (NH4)cMo7024 4H20 in 300 cc. of water, add a few drops of ammonia, and dilute to 1 liter. 0ne cubic centimeter is equivalent to about 0.005 gm. of lead. To standardize this solution, weigh 0.2 gm. of pure lead foil. Dissolve it in dilute nitric acid, add ammonia until the solution is alkaline, boil, acidify the solution with acetic acid, and titrate with the ammonium molybdate solution, using tannin solution on a porcelain pla...
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