1. AN APPARATUS FOR AUTOMATICALLY PERFORMING CHEMICAL OPERATIONS, COMPRISING, IN COMBINATION, A WORKTABLE, A MULTIPLICITY OF RECEPTACLES SUPPORTED ON SAID WORKTABLE CERTAIN OF WHICH AT LEAST CONTAIN LIQUIDS, A MULTIPLICITY OF PIPETTES ONE OF WHICH ACTS S A MAIN PIPETTE, A MOTORDRIVEN PUMP ROTATABLE IN BOTH DIRECTIONS, TUBE MEANS CONNECTING SAID PUMP TO SAID PIPETTES AND TO THE ATMOSPHERE SO THAT A FLUID MAY PASS THROUGH THE PIPETTES, MEANS FOR CONTROLLING SAID PUMP IN ACCORDANCE WITH THE DESIRED PASSAGES OF FLUID THROUGH SAID PIPETTES, AND MEANS SUPPORTING SAID PIPETTES ABOVE THE WORKTABLE FOR DISPLACEMENT PARALLEL TO THE AXES OF A SYSTEM OF THREE COORDINATES ONE OF WHICH IS VERTICAL IN ORDER TO BRING EACH PIPETTE IN VERTICAL ALIGNMENT WITH ANY RECEPTACLE AND SUBSEQUENTLY TO MOVE SAID PIPETTE DOWN AND UP WITH RESPECT TO SAID RECEPTACLE, WHEREBY LIQUID MAY BE REMOVED BY ANY PIPETTE FROM A RECEPTACLE AND DISCHARGED INTO ANY OTHER RECEPTACLE