. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 814 ORGANIC ANALYSIS. with other compounds being sufficient to vitiate the conclusions deducible from our experi- ments. Having ascertained the purity of our substance, the next care is to ensure its com- plete desiccation. For this purpose the fol- lowing plan, recommended by Liebig, will be found the most efficient (fig. 429). A small quantity of the material to be dried is placed in an inverted syphon-tube (c), the bend of •which is plunged into a vessel (D), contain- ing water gradually heated to the boiling point. W
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 814 ORGANIC ANALYSIS. with other compounds being sufficient to vitiate the conclusions deducible from our experi- ments. Having ascertained the purity of our substance, the next care is to ensure its com- plete desiccation. For this purpose the fol- lowing plan, recommended by Liebig, will be found the most efficient (fig. 429). A small quantity of the material to be dried is placed in an inverted syphon-tube (c), the bend of •which is plunged into a vessel (D), contain- ing water gradually heated to the boiling point. When plain water is used, the tem- perature of course will not rise above 212°; but by substituting for it different saline solu- tions we may at pleasure obtain any degree of heat between 212° and 300°, according to the nature of the compound to be analysed. A current of dry air is made to pass over the substance by connecting one limb of the sy- phon with a tube containing chloride of calcium (A), and the other with a vessel (E) closed at top, excepting the aperture by which it is con- nected with the syphon-tube, and rilled with water, which is allowed to run out at the bottom with a speed regulated by a stop-cock (/'), the place of the liquid being supplied by air, which has passed over the chloride of cal- cium and then through the syphon-lube. Vo- latile liquids that are unchanged by distillation should be allowed to stand two or three days upon fragments of fused chloride of calcium; the liquid should then be decanted and dis- tilled in a small retort; in other cases, as in the examination of fats or fixed oils, it may be more convenient to dry the material in a watch- glass placed in an ordinary water-bath or the hot- water oven previously described. The further progress of the analysis will vary according to the form and composition of the substance to be examined. We shall describe the methods of analysing— 1. A solid, which does not contain nitrogen. 2. A flui
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