In the first half of the twentieth century, almost all elevators had no automatic positioning of the floor on which the cab would stop. Some of the older freight elevators were controlled by switches operated by pulling on adjacent ropes. In general, most elevators before WWII were manually controlled by elevator operators using a rheostat connected to the motor. This rheostat (see picture) was enclosed within a cylindrical container about the size and shape of a cake. This was mounted upright or sideways on the cab wall and operated via a projecting handle, which was able to slide around the top half of the cylinder. COUNT 5
QSN1 Until the mid 1900s most elevators lacked what? ANS1 automatic positioning of the floor on which the cab would stop QSN2 How were most elevators built before 1939 powered?  ANS2 by elevator operators using a rheostat connected to the motor QSN3  Many earlier built  freight elevators were controlled by what? ANS3 switches operated by pulling on adjacent ropes QSN4 A rheostat is the size and shape of what? ANS4 a cake QSN5 Where was the rheostat mounted? ANS5 upright or sideways on the cab wall