Daniel J. Rankin
Published: 2013-09
Total Pages: 38
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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. 1901 edition. Excerpt: ...of no compound which would be formed from natural products by the method which would mislead by staining the ash a colour at all similar to the distinctive purple of finely divided gold. Small parts are chipped from all the sides of a mass of rock, amounting in all to about i-02.; this is finely powdered in a steel mortar, and well mixed; about half of it is placed in a capacious test tube, and then partly filled with a solution made by dissolving 20 grains of iodine and 30 grains of iodide of potassium in about 11cents oz. of water. The mixture thus formed is thoroughly agitated by shaking and warming; then after all particles have subsided, dip a piece of pure white filter paper in it, allow it to remain for a moment, then let it drain, and dry it over the spirit lamp. It is then placed upon a piece of platinum foil held by pincers and heated to redness over the flame; the paper is speedily consumed, and after heating further, to burn off all carbon, it is allowed to cool, and then examined. If at all purple, gold is present in the ore, and the relative amount may be approximately deduced as much, fair, little, or none. This method takes but little time, and is very trustworthy (see p. 171). Amalgamation Test. The following simple method for the detection of gold in quartz, pyrites, &c., is an adaptation of the well-known amalgamation process, and serves to detect very minute traces of gold. Place the finely powdered and roasted mineral in a test-tube; add water and a single drop of mercury; close the test-tube with the thumb, and shake thoroughly, and for some time. Decant the water, add more, and decant repeatedly, thus washing the drop of mercury until it is perfectly clean. The drop of mercury contains any gold that may hav
