Comprising glass U-shaped tube of about 15mm diameter, with one plain limb 220mm long and one graduated limb of overall length 120mm with graduations from 25 to 35x 0.2ml terminating in a bulb 37 mm diameter with third about 185x6mm (length x bore) attached at right angles to the plain of the other two limbs. A short length of the rubber tubing with two pinch clips of an short length of glass tubing mounted in end of wide-bore plain limb with rubber bung. Completely contained in a beaker of 1000ml capacity and stirre. all glass parts of barosilicate glass except beaker.