Some experimental studies of the vibrations of quartz plates

Numerous modes of vibration of and 30 degree cut circular and rectangular crfstSine quartz plates were studied experimentally Various methods were emoloved in studying these modes which are piezo-electncally excited The bThavfor o lycopodium powder applied to the vibrating faces proved to be the most fraitful source Sf information A number of photographs of the patterns th"; formed are produced and described.Although of limited utility two mechan- ^wifffiSi Concerning specially oriented "*?^£*^3°& ^vnpriTnPTital values of Young's modulus based on vibration frequencies 01 tne latter w re fouM to agree closely with corresponding values computed from a knownTeoretically derived expression.Rough experimental verification of the dfrecWon of one of the critical values of Young's modulus was obtained.Equations are derived for the modulus of rigidity «d J^^b r^wfor crystalline quartz as functions of orientation, and graphs of these two functions as well as of Young's modulus are given...,, mniin tine Methods are indicated, which may prove advantageous, of rigidly mounting quartz plates.