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 XXVIII. Intelligence and Miscellaneous Articles. 



ON A PROPERTY OF AN ELECTRIZED WATER-SURFACE. 

 BY G. LIPMANN. 



A MASS of water contained in a glass vessel is put in communi- 

 ■*"■ cation with the earth by means of a platinum wire. If a stick 

 of resin be rubbed and then brought near the water, positive electri- 

 city is drawn from the earth and distributed at the surface of the 

 water. The platinum wire, which serves as electrode of entry, has 

 a flow of positive electricity ; at it bubbles of oxygen gas are liber- 

 ated, in quantity proportional to the quantity of electricity entering : 

 at least this takes place if an electrode of very small surface is 

 employed, a "Wollaston point. The fact of the liberation of oxygen 

 under these circumstances is well known ; it has been verified, 

 notably by M. Buff and by M. Soret. 



After oxygen has been liberated, the hydrogen which was com- 

 bined with it remains in excess in the mass of water or else at its 

 surface. This excess, proportional to the charge, remains in some 

 way dissembled as long as the water is electrized; but at the 

 instant of the discharge the hydrogen is disengaged. 



The removal of the stick of resin suffices. The charge, which 

 was retained by influence, passes away into the earth through the 

 platinum point. This point serving as electrode of exit has a flow 

 of positive electricity ; it liberates bubbles of hydrogen gas. The 

 dissembled hydrogen is therefore found again during the discharge; 

 the whole of it is recovered. 



In fact, according to Earaday's law, the same quantity of electri- 

 city which liberates 1 equivalent of oxygen when it enters, sets 

 free precisely 1 equivalent of hydrogen at its departure. 



Since the whole of the dissembled hydrogen is to be recovered, 

 no part of it can be taken away by diffusion, or oxidation, or any 

 physical or chemical action that leaves the electric charge intact. 

 In other terms, the concealed hydrogen is neither • combined nor 

 dissolved ; and yet it is really there, since we can cause its liberation 

 by removing the stick of resin. 



Moreover the words dissolved or combined might be applied to 

 hydrogen retained in the interior of a mass ; but here, it seems, we 

 have a first instance of another order of material union. The dis- 

 sembled hydrogen is all held at the surface of the water — I mean, 

 in that portion of the body in which the electric charge is dis- 

 tributed. 



In fact, any portion whatever of the interior mass of water may 

 be replaced by air ; and as long as the surface is unchanged, the 

 charge of electricity and consequently the quantity of dissembled 

 hydrogen are unchanged also. Thus the mass can be hollowed out 

 without changing the quantity of the hydrogen ; this is therefore 

 Eound again at the surface. 



In the same way a mass of water electrized unequally, contains 

 at its surface an excess of hydrogen proportionate to the electric 

 charge. — Comptes Rendus de VAcad. des Sciences, August 9, 1875, 

 foI. lxxi. pp. 280, 281. 



