G. W. Pierce.-Crystal Rectifiers. 



Plate 





nmm/ *~ 



ii» ,i — n i nim«" . 



/ 





.->•* 



<4F 







^Pfe 



PS ; .. 







■"""V 





/"N 



*.*« | 





'■'■■ Si 



Proc. Amer. Acad. Arts and Sciences. Vol. XLIV. 



