File:The principles of chemistry (1897) (14586333309).jpg

Identifier: principlesofchem01mend (find matches)
Title: The principles of chemistry
Year: 1897 (1890s)
Authors: Mendeleyev, Dmitry Ivanovich, 1834-1907 Kamensky, George Lawson, Thomas Atkinson
Subjects: Chemistry Periodic law Argon
Publisher: London, New York, Longmans, Green and Co.
Contributing Library: Mugar Memorial Library, Boston University
Digitizing Sponsor: Boston University

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any surrounding objects. In order to separate the injuriousproducts, the gas is washed with water, a cylinder (not shown in the illustration) filledwith coke continually moistened with water serving for this purpose. The water commginto contact with the gas dissolves the ammonium carbonate ; hydrogen sulphide, car-bonic anhydride, and sulphurous anhydride, being only partly soluble in water, have tobe got rid of by a special means. For this purpose the gas is passed through moist limeor other alkaline liquid, as the above-mentioned gases have acid properties and aretherefore retained by the alkali. In the case of lime, calcium carbonate, sulphite andsulphide, all solid substances, are formed. It is necessary to renew the purifyingmaterial as its absorbing power decreases. A mixture of lime and sulphate of iron,FeSO,, acts still better, because the latter, with lime, Ca(HO),, forms ferrous hydroxide,Fe(HO).> and gypsum, CaS04. The suboxide (partly turning into oxide) of iron absorbs
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^ CAKJ50N AND THE IIYDROCAKDONS 363 As the decomposition of the organic matter which forms coal, is stillgoing on underground, the evolution of large quantities of marsh gas HoS, foiniing FeS and H.^0, and the gypsum retains the remainder of the ammonia,the excess of lime absorbing carbonic anhydride and sulphuric anhydride. (In Englishworks a native hydrated ferric hydroxide is used for removing hydrogen sulphide.)This purification of the gas takes place in the ajiparatus L, where the gas passes throughperforated trays iu, covered with sawdust mixed with lime, and sulphate of iron. It isnecessary to remark that in the manufacture of gas it is indispensable to draw off thevapours from the retorts, so that they should not remain there long (otherwise thehydrocarbons would in a considerable degree be resolved into charcoal and hydrogen),and also to avoid a great pressure of gas in the apparatus, otherwise a (juantity of gaswould escape at all cracks such as must inevitably exist in such

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