not shown as shown in fig3 and 4 the double siphon arrangement comprises a siphon tube 50 primarily located underneath measuring chamber 33 a first measuring chamber siphon 51 leads from measuring chamber 33 to siphon tube 50 a second timing chamber siphon 52 leads from timing chamber 34 to a point in siphon tube 50 which leads into centrifugally actuable shuttle type pump 53 as may be seen the open or inlet end 54 of siphon 51 is located within annular trough 38 since wall 37 see fig1 slopes towards this annular trough such location permits the full draining of the measuring chamber by the double siphon arrangement as will be more fully described hereinafter as seen in these figures one end 58 of impact tube 39 is angled so that agitator action causes tube end 58 to move relative to the contained liquid within measuring chamber 33 this causes the liquid to rise in impact tube 39 and be discharged into timing chamber 34 over a period of time through outlet opening 59 in impact tube 39 fig5 shows the timing chamber just prior to filling by the impact tube in one direction of rotation of the agitator the impact tube impacts the liquid causing it to enter the tube and forcing it to rise outlet opening 59 is positioned to be above the maximum fill level in the timing chamber liquid entering the impact tube under impact pressure rises and moves outwardly with centrifugal force aiding its flow since agitator action.