340 
DRS. J. AND B. HOPKINSON ON DYNAMO-ELECTRIC MACHINERY. 
Zero. 34 left. 
Deflection. 148 „ magnets made. 
,, 82 right; magnets short-circuited. 
Hence, deflection to right = 116 
„ left = 114 
Mean deflection = 115 
I. Four convolutions were then wound round the zinc plate and the cast-iron bed 
in a vertical plane, passing through the axis of the armature ; and the deflections 
noted : 
Zero . 
Deflection 
Zero 
Deflection 
5 ? 
Hence, deflection to right 
5? 
left 
15 left. 
61 ,, magnets short-circuited. 
40 right ; magnets made. 
11 left. 
64 ,, magnets short-circuited. 
36 right; magnets made. 
55 
46 
and deflection to right = 47 
,, left = 53 
in the two observations respectively, giving a mean =50*25; or, reducing to one 
convolution, =12*6. 
II. A square wooden frame, 38 cms. X 38 cms., on which were wound ten convolu¬ 
tions, was then inserted between the magnet limbs, with one side resting on the 
armature, and an adjacent side projecting 5 cms. beyond the coils on the limbs, or 
about 7'6 cms. beyond the cores of the limbs. The deflections were : 
Zero 
Deflection 
Hence, deflection to right 
,, left 
and ,, right 
,, left 
34 left. 
98 „ magnets made. 
22 right; magnets short-circuited. 
21 ,, ,, ,, 
81 left; magnets made. 
56 
64 
55 
47 
in the two observations respectively, giving a mean =55 ; or, reducing to one 
convolution, = 5'5. 
