Abstract
American Journal of Science.—August.—We notice the following papers:—The use of cupric nitrate in the voltameter and the electro-chemical equivalent of copper, by Frederick.E. Beach. Copper nitrate solution of density 1˙53 possesses certain advantages over the sulphate in voltameters. It is best to add one drop of saturated NH4Cl solution. The dependence of the amount of copper deposited upon the current density does not appear until a density of 0˙25 ampèeres per sq. cm. of electrode: is reached, and then it is counteracted by adding more NH4C1. With the nitrate, the weight of copper deposited is practically independent of the temperature between 10° and 35°. The solution may be used a number of times. The equivalent of copper as determined from the nitrate voltameter agrees to foar figures with that calculated from the best chemical determinations. But it is essential that the solution should be pure, and especially free from traces of nitrite.—On Mackintoshite, a new thorium and uranium mineral, by Wm. Earl Hidden; with analysis by W. F. Hillebrand. This is the original mineral of which thorogummite, discovered in 1891, is the alteration product. It is an opaque black mineral of hardness 5˙5, and resembles zircon and thorite in form. It differs from thorogummite by the further oxidation of the uranium and the assumption of one molecule of water. It contains three molecules of silica, one of urania, three of thoria, and three of water:—On the reduction of nitric acid by ferrous salts, by Charlotte F.Roberts. The volume of nitric oxide disengaged, swept along, by carbon dioxide and collected over caustic soda, was measured for the estimation of nitrates. The best results were obtained by passing the gas through KI solution before collecting,and estimating from the total volume of gas collected. Nitric oxide, being slightly soluble in caustic soda solution, must not be left long in contact with it. When the reaction takes place at high temperatures, some higher oxides of nitrogen may be formed, but this is corrected by the KI solution.—Concerning the structure of caoutchouc, by Hermann F. Lueders. Caoutchouc has no definite structure per se, and all apparent structure is only the result of the conditions under which its coagulation from the latex and subsequent solidification take place.
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Scientific Serials. Nature 48, 431–432 (1893). https://doi.org/10.1038/048431b0
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DOI: https://doi.org/10.1038/048431b0