502 E. P. TAYLOR. 
ees 
Cc 
CUuRRENTSUPPLY 
HAND 
CONTROLLED 
RHEOSTAT 
Oit DAMPER 
Fial 
The pole faces of the shoe brake were curved to fit the 
rim of the wheel, and it was found necessary to connect 
the brake to the end of the lever by a suspension link S 
pivotted both at the lever and at F on the brake as close 
as possible to the centre of contact between the latter and 
the wheel. By this means it was ensured that the length 
lL of the lever arm, at which the brake was producing a 
torque on the shaft, remained constant—provided the brake 
was allowed only aslight vertical movement. The height 
of the brake was, of course, so adjusted that the line join- 
ing the suspension pivot F and the centre of the shaft was. 
horizontal. The lever arm length 1 was, therefore, equal 
to the radius of the wheel plus the distance from the 
periphery to the suspension F. 
5. Description of the Author’s Method.—The most. 
important development in this brake retardation work was 
