With an ordinary flow the water stands at a certain height in the funnel, and, while this is so, the lever remains balanced; but if from any accident the flow is diminished, the level of the water in the funnel descends, the other arm of the lever falls, and in doing so releases two springs, one of which in flying up rings a bell, and the other by detaching a counterweight closes a cock and stops the supply of water altogether.

His disciples also failed to establish his doctrine in China, because it served the interests of an individual despot against those of the gentry as a class, and the middle class, which might have formed a counterweight against them, was not yet politically ripe for the seizure of the opportunity here offered to it.

After the unification of China, Korea had reason for seeking an alliance with the Turks, in order to secure a new counterweight against China.