considered as an Electrical P/icenomenon. 187 



overcome the cohesion of the particles of water, but not ef- 

 fected the separation of the glass. The surface of water vvhicii 

 has been torn away, and tliat which reniains in the cup, are 

 both equally good conductors; and hence a discharge from 

 one to the other takes place, in the same manner as in the act 

 of separating iron and mercury. 



That the capillary attraction of glass for water is nothing 

 more than an electrical phaenomenon, appears when we so ar- 

 range things as to be able to separate the touching surfaces 

 completely. In a conical vessel let some water be frozen, and 

 when perfect solidification has taken place, and no water is 

 present, pull the cone of ice out of the glass : examined at the 

 electroscope the glass and ice are found to be in opposite con- 

 ditions. Now is it not reasonable to suppose that the physi- 

 cal cause of the adhesion of ice to glass is the same as that of 

 water to glass? Does not therefore this experiment prove 

 that the capillary attraction of glass and water is only an elec- 

 tric phaenomenon ? 



II. If capillary attraction is nothing more than the result 

 of an electrical disturbance which ensues when bodies are 

 brought in contact with one another, we might expect that any 

 process which can change the electro-chemical relations of 

 such substances, could also probably alter their capillary phte- 

 nomena. 



The following experiments may be cited as substantiating 

 this view: — 1st. In a watch- 

 glass place a quantity of pure 

 mercury, A B, and upon it a 

 drop of water, C. Bring the 

 water in contact with the posi- 

 tive platina electrode of a vol- 

 taic battery of twenty or thirty pairs, and touch the mercury 

 with the negative. The moment the contact is made the 

 drop of water loses its spherical form, and spreads out into a 

 thin circular disc, wetting the surface of the mercury. The 

 diameter of the disc seems to be greater in proportion as the 

 battery is more powerful. 



Under ordinary circumstances water does not wet quick- 

 silver; a drop of water remains on the surface of quicksilvef 

 in the same manner that a drop of oil remains on water. As 

 soon, however, as their electro-chemical relations aredisturbet! 

 by the aid of a voltaic battery, the phaenomenon of wetting at 

 once takes place. 



2nd. Take a tube in the form of an inverted siphon, one 

 branch of which. A, is about half an inch wide, and the other, 



02 



