Ultrasonic Absorption in Castor Oil, Carbon Disulphide, Benzene and Xylene

ULTRASONIC absorption in some liquids has been measured by the method of heat development. The apparatus and its working was designed in such a way as to make it free from error due to the variation of generator power and also due to reflexion. A 3 Mc./s., 100 W. quartz generator produced the beam in liquid kerosine, contained in a vessel with cork paddings at the ends. In a small double-walled metallic vessel with asbestos packing, having a suitable coat of cement, two mica windows of 0.002 cm. thickness were fitted to allow the beam to pass in and out again after absorption. Two such vessels were made with exactly similar windows and different separations; the separations of windows were 3.6 cm. and 4.6 cm. Arrangements were made to place the front windows in the same relative position with respect to the quartz. The rise in temperature in these fairly non-conducting trap vessels, with different liquids, was measured in the steady condition. The electrical wattage to produce the same steady difference of temperature between the trap vessel and the outer kerosine was determined by a separate experiment. The temperature of the kerosine in the outer vessel was controlled by running ice-cold water around the vessel.