Licence: Public Domain Mark
Credit: Qualitative chemical analysis / by C. Remigius Fresenius. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![G Stannous chloride added in small quantity to solution of mer^ curio chloX^- to solutions of salts of —c ox.de m presence of On Lfdfug t ?at- q-kity of the reagent, the precipitated chlonde .s reduced to metal,^^^^^^^^^^^^ and the Precipitate, which was white at first, now acquires a gray tmt, and m W^er subsided, be readily united into g obules of me- un^^L^ry by boiling with hydrochloric acid and a httle stannous Y K a little galvanic element, made out of a slip of plaWm foil and a slip of tinfoil, joined at one end with a wooden c amp and else- There apax? from eLch other, be introduced into a solution of mercunc We aerified with hydrochloric acid, all the mercury will gradually be TecipSed, by preference upon the platinum. On drying the plati- Soil, roiling it up and heating it strongly in a g ass tube, globules of mercury wiU be obtained, which may be more distmctly seen under the microscope. On heating this mercury with a fragme^ of iodine, it wiU be converted into red iodide of mercury (Yan den Broek*). 8 Several other methods may be employed for the separation ot trace's of mercury from its acid solution by precipitation on metals (gold, platinum, copper, zinc). One of the most convenient of these furb?ingers';t is to render the solution ^^^'-^fy^^^^^^o^Z chloric siflphuric, or acetic acid, and warm it to 60 to 80 , trom 0-25 to 0-5 gram of unravelled brass wool or Dutch metal (Teubner J) is first roUed up into a ball and then teased out and put into the solu- tion with which it is left in contact with constant shaking for from five to ten minutes. The metal, which is now amalgamated, is washed Tvdth water (and if organic matters are present it is also washed with alcohol and ether) and dried between filter-paper ; it is then rolled into a cylindrical shape and placed in a piece of hard glass tube one end of which is drawn out into a capillary tube, the other end of the tube is then also drawn out into a capUlary tube close to the metallic plug, and the amalgamated metal is heated by slowly and regularly turning the tube round over a steady gas flame, until it approaches a low red heat. The mercury coUects in both the capillary tubes in the form of rings. Zinc also often forms similar rings, but m this case they are always situated nearer to the heated metal than the mercury ring If, after cooling the tube, a small crystal of iodine be placed near the mercury ring and gently warmed, the mercury is converted into a red incrustation of mercuric iodide, or if there is deficiency of iodine vapour, a crust of yellow mercurous iodide is formed. 9 The salts of mercuric oxide show the same reaction as tbe salts ot mercurous oxide with metallic copper, or when heated with carbonate of soda in a glass tube. § 120. b. Oxide of Copper or Cupric Oxide, CuO [CuO]» 1. Metallic copper has a peculiar red colour, and a brilliant lustre; it is moderately hard, malleable, rather difficultly fusible; in * Zeit. anal. Chem., 1, 512. + lUd., 17, 526, t Ibid., 19, 199. <JUAL. ^](https://iiif.wellcomecollection.org/image/b21966953_0169.jp2/full/800%2C/0/default.jpg)
