302 Mr. R. H. M. Bosanquet on the Present 



Electro-pneumatic Clock Governor. 



In all the applications of power useful for acoustic purposes, 

 every thing turns upon the steadiness of the motor and its 

 accurate regulation. I propose to indicate in outline how the 

 pneumatic and electro-pneumatic apparatus in use among 

 organ-builders will furnish convenient means of automatic 

 regulation by the clock. 



A good clock will close an electric circuit at every beat of 

 the pendulum for a time which must not be too short. This 

 current will communicate with an apparatus such as is em- 

 ployed in the electric action of the organ, in which air is ad- 

 mitted from a reservoir to a small power-bellows on closing 

 the circuit. In this way a ratchet-wheel will be pushed for- 

 ward a step every second. This drives a bevel wheel on the 

 same axis. Another bevel wheel opposite, moving freely on 

 the same axis, is turned in the opposite direction by the ma- 

 chine to be regulated. A third bevel wheel, with movable 

 axis at right angles to the first axis, gears in the other two 

 wheels. If the two other wheels move in opposite directions 

 with equal speed, the third simply turns round on its axis. If 

 either of the first two goes quicker or slower than the other, 

 the axis of the third moves with half the differential velocity. 



If this axis be attached to the governing arrangement of the 



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motor, the whole number of revolutions of the machine per- 

 formed in any length of time can be constrained to preserve 

 any desired ratio to the movement derived from the clock. 



The details would occupy more space than is desirable. I 

 will only say that pneumatic apparatus can be freely used with 

 advantage. The ordinary pneumatic key, connected with its 

 work by flexible tubing, and touched by a stud on the spindle 

 of any part of the machine to be controlled, forms a most 

 valuable resource for automatic regulation. 



Pneumatic Motors. 

 It will not be generally convenient to drive more than one 

 machine at regulated speed from the same motor. For this 

 and other reasons the employment of secondary motors, driven 

 from the bellows, will probably be of advantage. The form I 

 propose to give to these instruments is that of a three-crank 

 shaft and flywheel, with three power-bellows attached to the 

 three cranks. They will also be controlled by the clock 

 governor, with the assistance both of governed supply and 

 pneumatic brake. For the finer regulation of speeds I anti 

 cipate that the best results will be thus obtained. 



