OP ARTS AND SCIENCES. 



341 



TABLE OF GALVANOMETER DEFLECTIONS 

 d = <i 5 9 14 aa 3a 



47 



rf = 3 



14 



sa 



3» 



47 



The phase retardation is measured in degrees, one whole phase (or 

 period between two successive maxima or minima) being taken as 

 360°. The galvanometer deflections (see page 332 et seq.) are reduced 

 to a common unit through the known ratio of various shunts, the 

 greatest divisor being two hundred. The deflections due to a single 

 closing of the circuit, always in the same direction, are placed in line 

 with " V = 0." The divisions of the scale were about 5 mm. apart. 

 d and v represent in both tables the distance in inches between the 

 coils, and the velocity in revolutions per second. The galvanometer 

 deflections are, of course, only approximate ; but for small distances 

 and low velocities, the probable error of the phase-retardation will not 

 greatly exceed 5°. The curves of constant phase-retardation, at in- 

 tervals of 9°, are represented, graphically, below ; d and v being 

 understood as vertical and horizontal coordinates. 



