Use the assembly from Appartus1 except that a paddle formed from a blade and a shaft is used as the stirring element. The shaft is positioned so that its axis is not more than 2 mm from the vertical axis of the vessel at any point and rotates smoothly without significant wobble that could affect the results. The vertical center line of the blade passes through the axis of the shaft so that the bottom of the blade is flush with the bottom of the shaft. The paddle conforms to the specifications shown in Figure2 The distance of 25 ± 2 mm between the bottom of the blade and the inside bottom of the vessel is maintained during the test. The metallic or suitably inert rigid blade and shaft comprise a single entity A suitable two-part detachable design may be used provided the assembly remains firmly engaged during the test The paddle blade and shaft may be coated with a suitable coating so at to make them inert. The dosage unit is allowed to sink to the bottom of the vessel before rotation of the blade is started. A small loose piece of nonreactive material such as not more than a few turns of wire helix may be attached to dosage units that would otherwise float. An alternative sinker device is shown in Figure 2a Other validated sinker devices may be used