144 ACTION OF CENTRIFUGAL FORCE UPON LIQUIDS. 



of a strap, which passes round the shaft of the fly-wh 

 or some other convenient part of the engine, and then 

 round a driving- pulley fixed upon the vertical shaft. 

 When the speed of the engine is increased, centrifugal 

 force drives the balls apart, and in receding from the 

 shaft they move a collar which can slide loosely up and 

 down it, and is connected, by a series of levers, with the 

 throttle- valve which regulates the supply of steam: 

 this valve is thus partly closed, and the speed dimi 

 ishes. These balls keep the speed nearly uniform; f< 

 if it diminishes too much, they fall and thus open t 

 throttle -valve to a greater extent, allow more steam tc 

 pass, and the speed increases again. 



Centrifugal force acts upor 

 liquid and gaseous bodies in th( 

 same manner as upon solid bodies 

 One effect upon liquids has beei 

 studied already in the experiment: 

 on the flattening of a liquid globe 

 Fig. 102 is a section of a shallov 

 round glass vessel (the reservoi 

 of a paraffine lamp), with it 

 mouth, which is moderately wide 

 turned downwards. Opposite tj 

 it, it has a short stem which i 

 firmly inserted in a brass colla 

 provided with a handle. To thi[ 

 latter a stout piece of string, : 

 or 3 ram thick and 50 or 60 cm long, is tied, the otk 

 end of which is suspended by a hook from th 

 lower end of the axis of the whirling-table. Th 

 vessel being held mouth upwards, is half filled wit 



FIG. 102 ($ real size). 



