Fig. 6.
7. Tubes of natural size for collecting small portions of mercury by the process, p. [300].
8. Pipette, one-fourth the natural size, for removing by suction fluids lying over precipitates. Some have a rectangular bend in the upper part, by means of which the operator sees better the point of the instrument when in action; but such pipettes are difficult to clean. That represented in the figure is easily cleaned with a feather.
9. Apparatus for reducing the sulphurets of some metals by a stream of hydrogen. A, the vessel with zinc and diluted sulphuric acid, the latter of which may be renewed by the funnel B. C, a ball on the emerging tube to prevent the liquid thrown up by the effervescence from passing forward. D, E, corks by which C and G are fitted into F, the tube which contains the sulphuret at F. G, the exit-tube for the sulphuretted-hydrogen, plying into a vessel containing acetate of lead. When the hydrogen has passed long enough to expel all the air, the spirit-lamp flame is applied at F; and when sulphuretted-hydrogen is formed, the lead solution is blackened. The figure is one-third the size of the apparatus.
For Description of Figures 10 and 11, see p. [212].
Fig. 7.
Fig. 8.
