[29 bis] Manure which decomposes under the action of bacteria gives off CO2 and CH4.
[30] It is easy to collect the gas which is evolved in marshy places if a glass bottle be inverted in the water and a funnel put into it (both filled with water); if the mud of the bottom be now agitated, the bubbles which rise may be easily caught by the inverted funnel.
Fig. 58.—General view of gas works. B, retorts; f, hydraulic main; H and I, tar well; i, condensers; L, purifiers; P, gasholder.
Fig. 59.—Blowpipe. Air is blown in at the trumpet-shaped mouthpiece, and escapes in a fine stream from the platinum jet placed at the extremity of the side tube.
