This section is from the book "Cassell's Cyclopaedia Of Mechanics", by Paul N. Hasluck. Also available from Amazon: Cassell's Cyclopaedia Of Mechanics.
When the reciprocating motor described on p. 298 is used for organ blowing, an automatic speed regulator as shown by the accompanying illustrations will be required. In Fig. 1 the feeders are lettered F. The cord A passes over the pulleys B, one end being fastened to the top of the reservoir E, and the other to the lever C which actuates the valve. To keep the cord tight, two weights D are used. E is an ordinary 1-in. full-way valve; the screw spindle must be replaced by a plain rod to work through the stuffing box. The lever passes through an eye (Fig. 2) at the end of the spindle. The length of the lever c should be adjusted so that the friction of the valve spindle through the stuffing box is overcome, and also so that when the reservoir is full the valve is closed as shown. While the motor is not working the valve will be fully open. On opening the starting valve water will be admitted to the motor, which will now run at full speed. As the reservoir bellows fill, the regulator valve will gradually close, the speed of the motor being thus reduced. On air being withdrawn from the bellows, more water will be admitted, and the speed will increase; a constant air pressure will thus be maintained in the reservoir bellows.
Fig. 2. Regulator for Reciprocating Water Motor.