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: ...chlorides, etc. When a plant is burned these substances are found in its ash. Probably they do not all occur in the plant ...Read MoreThis 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: ...chlorides, etc. When a plant is burned these substances are found in its ash. Probably they do not all occur in the plant in the same forms in which they are found in the ash, the heat of combustion being doubtless responsible for new combinations. The essential salts of plants may form from 1.5 to 5 per cent. of their dry weight, where these only are to be had, but when much unnecessary salt is available, the percentage of mineral matter is usually much greater. 240. Qualitative Determination of Mineral Constituents. Besides the mineral substances already mentioned as necessary, many others also occur in plants, but for the present purpose it will suffice simply to notice those which are most common. Ash for analysis may be obtained by carefully burning a quantity of the tissue concerned. The ash should be separated into three parts, first by removing as much as will dissolve in water, then dissolving as much as possible of the remainder in hydrochloric acid, and retaining the residue insoluble in each. Boil the ash with water, filter and wash the residue (Solution I). Treat portions of this solution as follows: 1. Evaporate a portion to a small quantity and add hydrochloric acid. Effervescence indicates carbonic acid, probably from carbonates of alkali earths. If lead acetate paper is darkened by the escaping gas, sulphur in the form of sulphide is also present. 2. Treat another portion as in 1. Apply a few drops to yellow turmeric paper, and dry at gentle heat. Boric acid is indicated by a red color. Evaporate the solution to dryness and add very dilute hydrochloric acid. Allow to stand for a few minutes and filter. Divide the filtrate into two parts, (a) Add ammonium hydrate and magnesia mixture; phosphoric acid is indicated by a...Read Less
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