97 



be more satisfactory to give the construct- 

 ive data and results of a smaller machine 

 which has been at work. For this pur- 

 pose may be selected the machine to 

 which the characteristic curves, Fig. 11, 

 refer, and which has been exhaustively 

 tested by Mr. Brown, as already men- 

 tioned. The supporting-ring of this 

 machine is 31 inches in diameter and 3 

 inches wide. The core is of equal width 



Fig. 21 



and 8k inches deep, and is wound with 

 1,120 turns of wire arranged in fourteen 

 coils of 80 turns each. The resistance of 

 the armature when warm is 1.74 ohm. 

 The field-magnet cores are of cast-iron, 3 

 inches by 7 inches, with rounded corners, 

 and there are no pole-shoes. Each mag- 

 net-coil contains 140 turns of wire, and 

 the total resistance of the twenty-eight 

 coils is 1.73 ohm. The calculated 



