THE TIME OF ACTION.

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other body is necessary, thus allowing to the inquirerthe unimpeded use of both his hands. A vane con-nected bv a train of wheels, and set in motion by aheavy weight, has also on some occasions been em-ployed in chemical processes, to keep a solution in astate of agitation. Another object to which a similarapparatus may be applied, is the polishing of smallspecimens of minerals for optical experiments.