194 



as in Fig. 39. Arrangements were made 

 that the inner turns might be progress- 

 ively cut out, so as to virtually remove 

 wire from each coil. Under static condi- 

 tion, or no load, the terminal electromo- 

 tive force was practically unchanged, 

 even though considerable fractions of 

 wire- turns were cut out from the center 

 of each coil. But under a load a limit 

 was soon found, or a point reached, in 

 which the electromotive force was the 

 maximum under a given excitation of the 

 field. This maximum was reached after 

 a few turns had been removed or cut 

 out ; and the open space in the center of 

 the coil so obtained was adopted for use 

 in the apparatus subsequently manufact- 

 ured on the large scale. The vacant 

 space was less than one-half the width of 

 the pole-face. The relations would be 

 as shown in Fig. 40. He regarded this 

 result as in a measure growing out of the 

 condition of displacement of lines, indi" 

 cated in Fig. 41, where the current in 

 the armature- coil drew the lines together, 

 leaving the field, or bunched them 



