The Analyst, Volumes 16-17

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Royal Society of Chemistry, 1891 - Chemistry, Analytic
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Page 17 - Introduce asbestos fibresf so as to fill about half of the bulb. Draw air through while drying, cool and weigh. Connect with aspirator, filter the precipitated Cu2O, wash with hot water, then, having changed the receiving flask, wash twice with absolute alcohol and twice with ether. Having removed the greater part of the ether by an air-current, connect the upper part of the filter tube by means of a cork and some glass tubing with a hydrogen apparatus, and heat with a small flame, whose tip is about...
Page 127 - After repeated trials the following course, combining a number of well-known methods, has been found to be the most satisfactory. The silica and bases are determined by the ordinary sodium carbonate fusion method, in which the hydrates of titanium, chromium, iron, and aluminum, together with the phosphoric acid, are precipitated together, and, after weighing, fused with sodium bisulphate, dissolved, the small amount of silica separated, and the solution, after reduction of the ferric oxide, titrated...
Page 127 - About 25 cc. of dilute hydrochloric acid (i :5) is now added, the stirring being continued, and the material is then evaporated on the water-bath until most of the hydrochloric acid has been driven off. The material is then washed into a beaker, and any residue adhering to the vessel can be removed by a few drops of hot, strong hydrochloric acid, the vessel being rubbed with a bit of paper if necessary. If the solution be very turbid it can be digested on the water-bath for some time, but ultimately...
Page 147 - ... contained in an iron vessel. This vessel is provided with a lid which screws on airtight, pierced with four apertures through which pass air-tight, respectively, the pear-shaped bulb, a thermometer, a thermostat, and a long tube open at both ends to condense any mercury which may volatilise.
Page 151 - The first portion of water should be added drop by drop, and the flask shaken between each addition in order to avoid foaming. When the soap is dissolved, 5...
Page 82 - ... given their assent to it, and that they will at times produce milk below standard. A bad season for hay-making is, in my experience, almost invariably followed by a particularly low depression in the quality of milk, toward the end of winter. Should the winter be of unusual severity and length, the depression will be still more marked. Long spells of cold and wet, as well as of heat and drought, during the time when cows are kept on pasture, also unfavorably influence the quality, and, I may...
Page 117 - No person shall sell to the prejudice of the purchaser any article of food or any drug which is not of the nature, substance, and quality of the article demanded by such purchaser...
Page 17 - Take an aliquot part of the filtrate, add sodium sulphate to remove any lead present, make up to a definite volume, and filter. It is best to arrange the dilution so that the 50 cc of this filtrate, which are to be used for the determination of the total reducing sugar, will precipitate between 200 and 300 mgrs.
Page 128 - ... precipitation proved complete. The precipitate is dissolved in hot dilute hydrochloric acid. The filter, after washing, is burned in a large platinum crucible, into which the solution, concentrated to a small bulk, is put and evaporated on the water-bath till it becomes pasty. Just enough water is now added to dissolve the salts, and then dry sodium carbonate is added in small portions, with continual stirring, till a comparatively dry mass results. This must be carefully done, for if too much...
Page 127 - When the solution is so far evaporated that fumes of sulphuric acid begin to come off, there should still be so much acid present as to form a solution or emulsion and not a paste, since the paste is liable to bake on the bottom of the vessel and form the difficulty-soluble anhydrous sulphates produced by overheating, especially when magnesia is present in quantity.

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