810 



PROCEEDINGS OF THE AMERICAN ACADEMY 



The following show the results obtained by varying the size of the 



bars or wires forming the armatures ; 



TABLE II. — Diameter of Bar, 2.5 mm. 



TABLE in. — Diameter of Bar, 3 mm. 



Bars of various small diameters were used with results correspond- 

 ing to those given in the above tables. It was evident that the size 

 of the armature had very little effect upon the induced magnetism, or 

 upon our testing induced currents. To determine this point, we made 

 a series of determinations of the strength of the induced currents which 

 resulted from the employment of armatures of various sizes. The 

 results are contained in the following table : — 



This fact has an important bearing upon the practical construction 

 of magneto-electric engines ; for it seems that we can vary the size of 

 magnetic revolving armatures, within large limits, to suit considerations 

 of speed, &c., without affecting materially the induced currents, through 



