The apparatus is shown in Fig. 1.2. A test tube is fitted with a two-hole stopper. Through one hole is fitted the capillary tube (a length of a thermometer cut to expose the capillary at both ends). This is fitted through a glass sleeve and held in place by a piece of rubber tubing. In the second hole is a tube through which pressure or suction can be applied. This test tube apparatus is immersed in a water bath to allow control of temperature. The water bath should be set at 25°C.