SONIC EMULSIFICATION 295 Figure &--Raytheon Model DF101 (250 Watt) sonic oscillator, Raytheon Manufacturing Co., Waltham 54, Mass. Figure 4.--Jet-blade assembly of Minisonic Mark II hydrodynamic generator. Key: A, Jet B, ground edge of blade C, blade retaining screws D, jet locking collar E, vibrating blade F, resonant bell.

296 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS system with the tubular crystal installed in a line and driven by a generator. Some equipme. nt, designed for dispersion use, has employed this type of transducer assembly. MAGNETOSTRICTION GENERATORS In the presence of an alternating magnetic field certain metals such as nickel and its alloys will be periodically elongated and contracted, thus setting up vibrations. This is the principle of the magnetostriction gen- erator. The alternating magnetic field is adjusted to the natural frequency of the metal rod, which can be laminated to reduce eddy currents. This type of transducer assembly can be so constructed that the vibrating rod Figure 5.--Minisonic Mark II homogenizer, Sonic Engineering Co., Stamford, Conn. is placed directly in the liquid to be treated, so that there is no energy loss due to absorption or reflection by the treatment container. Many types are available for commercial cleaning applications or for the processing of small amounts of material in the laboratory. Figure 3 shows a laboratory unit of this type designed for research in the area of disintegration, emulsification, acceleration of chemical reactions, etc.