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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1885 Excerpt: ...placed in the generator, and everything being in position, the apparatus is filled with hydrogen by the use of a small quantitv of acid No. 2. After a sufficient time has elapsed, the gas is lighted at the jet, and the glass tube heated to a bright redness. The arsenical solution in concentrated form is mixed with 45 cc. of acid No. 2, and the mixture passed into the separating funnel, from which it is allowed to flow into the generator at such a rate that the entire fluid is introduced in one hour or one and a half; 40 cc. of acid No. 3 are then added and allowed to flow slowly into the generator, . and lastly, 45 cc. of acid No. 4. The amount of time required will vary with the amount of arsenic: 2 to 3 mgrms. of arsenic will require about two to three hours for the entire decomposition, while 4 to 5 mgrms. will need perhaps three to four hours. Where the amount of arsenic is small, only 25 grms. of zinc are needed, and but 45 cc. of acid No. 2, 30 cc. of acid No. 3, and 30 cc. of acid No. 4; but when 4 to 5 mgrms. of arsenic are present, it is better to take the first mentioned quantities of zinc and acids. The arsenic being thus collected as a large or small mirror of metal, the tube is cut at a safe distance from the mirror, so that a tube of perhaps 2 to 6 grms. weight is obtained. This is carefully weighed, and then the arsenic removed by simple heating; or, if the arsenic is to be saved (as in a toxicological case), dissolved out with strong nitric acid. The tube is then cleaned, dried, and again weighed, the difference giving the weight of metallic arsenic, from which by a simple calculation the amount of arsenious oxide can be obtained. Some test results are given as follows; they were obtained by introducing definite quantities of arsenious oxide ..

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