VIBRATIONS OF PARTICLES OF WATER. 153 



is continually changing from a vapory to a liquid 

 state, and from a liquid to the solid polarized state 

 of crystals of ice, yielding to the alternate predomi- 

 nance of the orbital and axial forces in summer 

 and winter. It is on account of this peculiar ex- 

 citability that water in continual motion is so 

 extensively diffused over our planet. 



The vibratory movements of the particles of 

 steam are represented by rapid vibrations of nu- 

 merous light pith-balls 

 placed beneath a bell- 

 glass, and excited by 

 the electric action 

 transmitted between 

 two brass balls ; as in 

 Fig. 58. The pith- 

 balls are first impelled 



toward the upper brass 

 ball, and then toward 

 the lower one, with 

 such rapidity as to re- 

 semble a misty vapor 

 filling the jar. 



The similar quick 

 vibrations of steam 

 in a cylinder beneath Fi *' s8 * 



a piston drive out the particles of air therefrom, 

 and occupy their places, impinging against the 

 under side of the piston, and counterbalancing 

 the force of the particles of air impinging upon 



