. A treatise on pharmacy for students and pharmacists. ter of crystallization has been expelled and the powder hasceased losing weight. Dried alum, dried sulphate of iron, and dried sulphate of copper are preparedby exsiccation. Exsiccated oranhydrous salts may be restoredto their original composition bysimple solution in water. Desiccator is the name appliedto glass apparatus of varied con-struction, in which substances,after having been completelydried by heat, are allowed to coolin air which is kept entirely freefrom moisture by strong sul-phuric acid, fused calcium chlor-ide or freshly-bur
. A treatise on pharmacy for students and pharmacists. ter of crystallization has been expelled and the powder hasceased losing weight. Dried alum, dried sulphate of iron, and dried sulphate of copper are preparedby exsiccation. Exsiccated oranhydrous salts may be restoredto their original composition bysimple solution in water. Desiccator is the name appliedto glass apparatus of varied con-struction, in which substances,after having been completelydried by heat, are allowed to coolin air which is kept entirely freefrom moisture by strong sul-phuric acid, fused calcium chlor-ide or freshly-burned lime, placedin the lower cup of the the desiccator is alsoused to abstract moisture frommaterial which, owing to its volatile nature, cannot be exposed toheat without loss or injury, and since sulphuric acid and lime bothhave a great affinity for water, perfect desiccation can thus be 155 represents one of the styles of this very useful apparatus,which is indispensable in quantitative chemical analysis. Fig. Desiccator. Incineration, Calcination, and Torrefaction. Incineration, or reduction to ash, is a process of separation appliedto vegetable matter, which consists in heating it to redness in open SEPARATION OF VOLATILE MATTER. 159 vessels, with full access of air, until all carbon has been consumed,or converted into carbon dioxide. Calcination differs from incineration chiefly in being applied tomineral substances, which are heated to redness without fusion, forthe purpose of expelling some volatile constituent at a high heat, asthe carbonic acid from magnesium and calcium carbonates in thepreparation of magnesia (calcined) and unslaked lime, or the nitricacid from mercuric and cupric nitrates in the preparation of therespective oxides. Torrefaction, or roasting, is not so much a method of separationas one which is intended to modify the properties of substances byexposing them to dry heat to a point short of
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Keywords: ., bookcentury1800, bookdecade189, booksubjectpharmacy, bookyear1895
