The Commercial Hand-book of Chemical Analysis; Or, Practical Instructions for the Determination of the Intrinsic Or Commercial Value of Substances Used in Manufactures, in Trades, and in the Arts

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George Knight and Sons, 1850 - 640 páginas
 

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Página 92 - The instrument consists of a spirit-lamp, surmounted by a small boiler, into which a large cylindric glass bulb is plunged, having an upright stem of such calibre, that the quicksilver contained in them, may, by its expansion and ascent when heated, raise before it a little glass float in the stem, which is connected by a thread with a similar glass bead, that hangs in the air. The thread passes round a pulley, which turning with the motion of the beads, causes the index to move along the graduated...
Página 99 - ... of sugar to the 100 gallons. To Chemists for their tinctures, &c., this instrument will be found essentially useful. NB — Care must be taken that the mercury is entirely in the bulb of the thermometer before it is fixed on the stem for operation, and in all cases (except for water) the salt must be used. CONCLUSION-. Wines are peculiarly subject to be mystified by adulterations of various kinds. It will prove of great advantage to the public when the relative quantity of frmt, or saccharum,...
Página 171 - Unfortunately, however, many of the preparations of the cocoa-nut sold under the names of chocolate, of cocoa flakes, and of chocolate powder, consist of a most disgusting mixture of bad or musty cocoanuts, with their shells, coarse sugar of the very lowest quality, ground with potato starch, old sea-biscuits, coarse branny flour, animal fat (generally tallow, or even greaves).
Página 91 - THAT tlie boiling temperature of water is increased by holding neutro-saline and saccharine substances in solution has been long known, and has been the subject of many experiments, made partly with the view of ascertaining from that temperature the proportion of the salt or sugar, and partly with the view of obtaining a practical liquid bath. But it seems to have been reserved for the...
Página 91 - Brossard-Vidal constructed an instrument for determining by that temperature the proportion of alcohol present. His chief object was to furnish the Revenue Boards of France with a means of estimating directly the proportion of alcohol in wines, so as to detect the too common practice of introducing brandy into their cities and towns under the mask of wine, and thereby committing a fraud upon the octroi ; as the duty on spirits is much higher than on wines. The...
Página 266 - ... of the bulb condenser. The bulb condenser should then be disconnected and emptied into a porcelain capsule ; an excess of a solution of chloride of platinum is added to the acid-liquor, and the whole is slowly evaporated to dryness in a steam-bath. The residuum should be treated with a mixture of two volumes of alcohol and one of ether, in order to dissolve the excess of chloride of platinum employed, and the ammonia chloride of platinum thus obtained, being washed with the above mixture, until...
Página 151 - ... had been defective and of inferior quality, recourse had been had to the expedient of colouring the commodity •with vermilion. Even this admixture could not be considered deleterious. But on further application being made to the druggist who sold the article, the answer was, that the vermilion had been mixed with a portion of red lead; and the deception was held to be perfectly innocent, as frequently practised on the supposition, that the vermilion would be used only as a pigment for house-painting....
Página 151 - ... with so harmless an adjunct. Thus, through the circuitous and diversified operations of commerce, a portion of deadly poison may find admission into the necessaries of life, in a way which can attach no criminality to the parties through whose hands it has successively passed.
Página 415 - This having been found out, small quantities of the suspected are added to a perfectly pure oil of the kind under examination. Every mixture is then tested by the re-agents, until precisely similar results are obtained as those yielded by the oil under examination. Thus the proportions of the two mixed oils will be discovered by approximation.
Página 96 - ... the liquid, then insert the saccharometer, to ascertain its present gravity or density per barrel, and at whatever number it floats that will indicate the number of pounds per barrel heavier than water. Example 1. — Suppose the saccharometer to float at the figure 8, that would indicate 8 Ibs.

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