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. 1839 edition. Excerpt: ...History.--Iodine and potassium are contained in sea-water, as well as in sea-weeds, but whether the iodine is in combination with potassium or with some other metal (sodium or magnesium) it is impossible to say with certainty. Preparation.--There are two principal methods of procuring this salt. (a.) Process of the Pharmacopeia.--This consists in adding two ounces of iron filings to six ounces of iodine mixed with four pints of water, stirring them frequently with a spatula for half an hour. Apply a gentle heat, and, when a greenish colour appears, add four ounces of carbonate of potash, first dissolved in two pints of water, and strain. Wash the residue with two pints of boiling distilled water, and again strain. Let the mixed liquor be evaporated, that crystals may be formed. The theory of this process is as follows:--One equivalent or 126 parts of iodine combine with one equivalent or 28 parts of iron. The resulting iodide of iron is decomposed by one equivalent or 70 parts of carbonate of potash, by which one equivalent or 160 parts of iodide of potassium and one equivalent or 58 parts of protocarbonate of iron are procured. 1 eq. Iodide cl eq. Iodine. 126 1 eq. IodidePotasTM. 166 Iron 154 (I eq.Iron.. 28 leqCarb" 0 eH-Potassium 40. Potash 70 51 el-xygen 8-/u eq.Carbon.A'1.22. ==» I eq. Carb". Iron. 58 (b.) Dr. Turner's process.--This is the simplest, and I believe the most eligible method. It consists in adding to a hot solution of pure potash as much iodine as the liquid will dissolve, by which means a reddishbrown fluid is obtained. Then pass hydrosulphuric acid through the liquid until it becomes colourless. Apply a gentle heat, to expel any excess of the acid; filter to get rid of the free sulphur, and exactly neutralize...
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