In one end, a circular brush is introduced, and against this the moulds to be cleaned are firmly pressed. In consequence of the large number of revolutions which this brush passes through, the moulds are cleansed of still adhering masses of chocolate in a half or third of the time occupied when hand labour is employed. At the other end of the shaft occurs a duster, sprinkled with Vienna white (a lime), which polishes off the moulds previously and thoroughly cleaned by the circular brush. The great advantage of this machine is that the daily expenditure on polishing is considerably reduced One girl can do the work of two hand workers, when this machine is employed. In addition, it makes possible a continual touching up of the material used in the making of the moulds, a ventilating apparatus removing all traces of dust. [Illustration: Fig. 53.] 12. ~The Shaking Table.~ The pasty chocolate mass fills itself into the chocolate moulds spontaneously, in consequence of its soft consistency. Yet to share it evenly throughout the mould, so that it adapts itself to every bend and hollow there occurring, and further to bring to the surface any possible bubbles of air evident in the mass, the chocolate is whilst still in the moulds subjected to brisk shaking. This is effected by placing the chocolate on trays and transferring these to the shaking table, of which types and construction are at the present time manifold and various, the best and oldest being given in front elevation below (Fig. 54). [Illustration: Fig. 54.] The movable slab =a=, fitted with an upright rim at its edges, has underneath two projecting pieces =d=, working against deeply toothed wheels =e=, which fastened on the shaft =b=, are driven round by the pulleys =c=. The teeth of the wheels catch on the projecting pieces at every revolution of the shaft and push them rather gently on one side, and when the tooth-points slide from under the slab, it drops down as much as it has been previously raised. Each tooth of the wheel coming into contact with the projections, the same motion is repeated several times, causing the slab to oscillate up and down. This oscillation of the slab is controlled by means of a hand lever =f=, occurring on the shaft =g=, and fixed crosswise thereon, so that we can only show it in cross section on the diagram. The lever =f= attaches itself to the under part of the slab, raises it, and so throws the wheels out of contact with the projecting pieces, but without stopping the rotation of the shaft =b=. Shaking tables have also witnessed considerable improvements with the lapse of time, and we shall now proceed to treat these in more detail, especially as several recent constructions offer and illustrate many interesting mechanical points. [Illustration: Fig. 55.] [Illustration: Fig. 56.]