employed as a moving Power. '263 



which moves on the pivot 6, and is prevented by the screw- 

 head 7 from moving beyond a certain point to the left, whilst a 

 very delicate spring 8 causes it to regain that point after it has 

 been removed from it. At the lower end of the crutch are 

 two pins 9, which receive between them the pendulum. The 

 wheel 10 has sixty teeth, and is supported by the cock 11. 

 When the pendulum moves to the right, the upper end of the 

 crutch moving in the contrary direction, and the spring 8 yield- 

 ing, allows the fever 5 to clear one tooth of the wheel; but when 

 it moves to the left, the screw-head 7 stopping the lever, the 

 wheel is caused to move through the space of that tooth, the 

 elbow 12 dropping between two teeth at the other part of it, 

 and keeping it steady. 



The wheel 13 has also sixty teeth, and is moved in a similar 

 manner by the lever 14, which carries the small lever lo. 16 is 

 a pin which acts upon the lever 14 at every sixtieth vibration; 

 and consequently if the wheel 10 make one revolution in a mi- 

 nute, the wheel 13 would make one revolution in an hour. 

 Any number of wheels might of course be set in motion, if the 

 maintaining power on the pendulum were sufficient to overcome 

 the friction and inertia. Tiie indexes are fixed to the pivots on 

 the other side of the dial plate. ,It will be easily understood by 

 recurring to fig. 1, that the vibrations of the pendulum are main- 

 tained bv the successive charges of electricity which the cork 

 ball receives firom the positive end of the column, and its dis- 

 charges at the cross wire No. 2, where a small spark is always 

 perceptible. 



It may be also easily conceived that the rapidity of the vibra- 

 tions is influenced by the variations in the electromotive power 

 of the column, which are occasioned by the circumstances stated 

 by M. De Luc, Mr. Singer, and myself, viz. heat, moisture, anfl 

 the electricity of the ambient air. Whilst engaged in the con- 

 strviction of this apparatus for the purpose above stated, it oc- 

 curred to me, that if the power of the column were sufficient to 

 make the pendulum vibrate as fast as seconds in all tempera- 

 tures, and under all other circumstances, it would be possible to 

 draw off the superalnmdant electricity which at high tempera- 

 tures, &;c. mafle it \\hx?ite faster, as quickly as it accumulated; 

 and after several trials I adopted the following method, by whicli 

 I succeeded better than 1 expected to have done, in regulating 

 the vibrations. 



No. 17, fig- 1, is a similar piece of brass to 4 ; it carries the 

 support of the screw 18: tliis terminates in a fine point, and 

 passes through the disk 19, which can be placed at any required 

 distance from the point to be ascertained by experiment, and can 

 also be advanced to or withdrawn from the cork ball ivitk the 



R 4 point. 



