396 TENTH ANNUAL REPORT OF 



sage of the electrical current from a metal into a liquid, but that it 

 perceptibly favors the passage of the current from a liquid to a metal. 



Vorsselman de Heer opposed this singular opinion. He ascribed 

 the action not directly to heat, but to the motion of the liquid pro- 

 duced by boiling, and by which the polarizing gases were removed 

 from the electrodes. He supported his view by the fact that the same 

 effect can be produced without heat, by merely agitating the plate 

 slightly in the liquid, or causing motion in the liquid near the plates 

 by a glass rod. 



He took a voltaic pile of five pairs charged with pure water. Two 

 platinum wires dipped in a glass of distilled water, forming the poles 

 of the battery, the galvanometer placed in the circuit indicated 45° ; 

 this deflection, however, rapidly decreased on account of the increas- 

 ing polarization, but it always increased again when the negative 

 wire was shaken. The following results were obtained : 



After 15' 34° ; the negative wire being shaken, 40° 

 After 30' 16° ; do. do. 38° 



After 60' 4° ; do. do. 32° 



Shaking the positive wire had no influence. 



Similar results were obtained with copper wires. 



Vorsselman' s explanation is certainly the correct one, yet he leaves 

 unexplained the circumstance of the positive pole being unaffected by 

 heating or shaking. Is it because oxygen adheres more firmly to 

 platinum plates than hydrogen ? 



According to a notice in the " Jahresbericht iiber die Fortschritte 

 der Chemie, Physik u. s. w. von Liebig und Kopp, Giessen 1849, s. 

 297," r>ecker of Griessen has investigated more minutely the decrease 

 of polarization at increasing temperatures of the decomposing fluid ; 

 but his labors have not yet been published. 



.§ 39. Cause of galvanic polarization. — One of the first who opposed 

 the hypothesis of resistance to transition, and endeavored to estab- 

 lish the existence of an electro-motive opposing force in the voltameter, 

 was Schonbein. AVhile all the researches on this subject, hitherto 

 considered, rested upon the relation of the passage of the current 

 through electrolytes, to Ohm's law, and while they were in this way 

 led indirectly to the view that galvanic polarization was to be ascribed 

 to the strata of gas covering the electrodes, Schonbein regarded the 

 subject from an entirely different point of view, and sought to prove 

 directly the polarizing influence of gases on metallic plates. 



The most important of Schonbein's memoirs on this subject are the 

 following : 



Ohse7'valions on the electrical 'polarization of solid and liquid conduo- 

 tors. (Pog. Ann. XLYI, 109.) 



Neto observations on voltaic polarization of solid and liquid conduc- 

 tors. (Fog. Ann. XLVII, 10!.) 



On voltaic polarization of solid and liquid bodies. (P. A. LVI, 135.) 



I will here state the essential results of Schonbein's researches, 

 without reporting upon the contents of these separate papers. 



The following experiment is mentioned on page 199 of the second vol- 



