102 



KENNELLY-TAYLOR— EXPLORATIONS OVER [April 22, 



expression M^2L//cos^ may be called the magnification-factor 

 of the explorer. As ordinarily employed, 2L = 5o cm., / = o.o5 

 cm., = 45° approximately, or cos ^^0.7; so that M= 1,400 

 approximately, varying in different sets of measurements between 



Beam of Light 

 from Arc. 



e^ilcos4> 



Mirror 

 \ ^Diaphra(^rn 



\>_A : 



Dotted lines refer to 

 deflected position of 



diaphraam. 



Fig. 6. Diagram Showing Action between Mirror and Diaphragm in Explorer. 



800 and 1,500. Had it been necessary, this magnification-factor 

 might have been considerably increased, by increasing the distance 

 L between mirror and scale ; although the reduction in luminous- 

 spot intensity, at increasing ranges, prevents the precision of the 

 observations from increasing in the same proportion as the magni- 

 fication-factor. At L = 25 cm., the amplitude of luminous band 

 could be read to o.i mm. on the graduated translucent scale F. 



Source of Diaphragm Vibrations. 



Two sources of vibrations were used in different series of tests, 

 (i) acoustic, (2) electromagnetic. 



