The Proceedings of the Iowa Academy of Science Volume 15
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1908 edition. Excerpt: ...nor in the uric acid eliminated under similar conditions by Subject B, also of the danger of drawing too positive conclusions from a single experiment in physiological chemistry, final decision should be postponed. The experiments seem to clearly indicate that neither of the hydroxy-benzoic acids affect nitrogen metabolism except in the case of uric acid. Furthermore, when the side chains are in the ortho position the uric acid is increased in the urine; when in the meta or para positions this is not true. If Emil Fischer's hypothesis be correct that in order to produce decomposition a ferment must have a configuration corresponding to that of the compound which It changes, we can apply it here to explain the different effects of these three isomeric substances; otherwise we must await the discovery of additional facts to devise a more rational theory. THE DETERMINATION OF FERROUS IRON. BY NICHOLAS KNIGHT. Robert Mauzelius, in the Geological Survey of Sweden (Sveriges Geol. Underseekning), calls attention to a universal defect in the estimation of ferrous iron in minerals and rocks. He finds that a considerable error arises from grinding the rock in the ordinary way to a fine powder, owing to the oxidation of ferrous to ferric iron. If the specimen is reduced to a coarse powder instead of being finely pulverized, a more accurate result is attainable. This source of error has hitherto escaped the attention of analysts. We have investigated specimens of siderite with a view to determine the oxidation effect when the mineral is finely pulverized. In each case only the ferric oxide was estimated, and the method of Berzelius as modified and improved by Bunsen was employed. About a grm. of the specimen was weighed each time in a 200 cc. flask...
- Paperback | 56 pages
- 189 x 246 x 3mm | 118g
- 13 Sep 2013
- Illustrations, black and white