S^o On the Caufes of the Galvanic Phendmna. 



pofcd to about twenty-two cubic inches of nitrous gas for three days, dlmlniflied It one- 

 fourth, and fome of the gas was rendered abforbable by water. 



d. The formation of nitrous gas, nitrous oxide, and ammoniac, when very weak folu- 

 tions of nitrous acid are made to oxidate zinc, 'demonftrate both the decompofition of the 

 acid and the water. 



e. The oxidation of zinc in folutions of marine and fulphuric acids in water, appears to 

 be owing to the affinity which has been called predifpofing. 



4. The Galvanic Pile of Sigfior Volta feems incapable of aEling when the Water between the 



Pairs of Plates is pure. 



The word pure is here ufed in the fame fenfe as in i. 



a, I have found, by numerous experiments, that the galvanic pile introduced into 

 hydrogen, through common water, ceafes to evolve gas In the tube, and to adl in about five 

 or fix minutes, »'. e. in about the time required to confume the atmofpheric air diflblved in 

 the common water between its plates. The phenomenon is exa£tly the fame in nitrogen, 

 nitrous oxide, and hydro-carbonate. The aftion of a pile, as known by Its power of 

 evolving gafes from water, Is dlmlnifhed Immediately on Its Introdudlion Into thofe gafes. 

 It ceafes in them nearly in the fame time, and cannot be reftored by admitting frefh gafes of 

 the fame kind, though, as will be feen In the next fe£tion. It Is Immediately reftored 

 by Immerfing the pile for a moment In water faturated with atmofpheric air. 



b. I have found, by numerous experiments, made with the afliftance of my friend, 

 ^r. King, that the galvanic pile ceafes to aft in vacuo when the gage is at about -^^ of 

 an inch, even though the poles are conne£led by wires with the atmofphere, and the water 

 it Is made to aft upon In contaft with the atmofphere. 



5, The Pile a£ls when the Water between the double Plates holds in Solution Atmofpheric Air, or 



Oxygen, or Nitrous Gas, or Nitrous Acid, or Marine Acid. 



This faft I have proved by numerous experiments. — a. A pile afted in atmofpheric 

 air, included in a glafs cylinder over water for two days, till nearly all the oxygen of the 

 air was confumed. — b. A pile decompofed water much more rapidly in oxygen than In 

 common air, and lefs rapidly In nitrous gas than in common air. — c. That the influence of 

 an elaftic oxygenated atmofphere is not eflentlal to the galvanic efFefts, is evident from the 

 faft of the conftant reftoration of the powers of a pile after they had ceafed to appear In the 

 hydrogen, nitrogen, &c. by momentary immerfion In water faturated with atmofpheric air. 

 In thefe experiments the piles were plunged Into the water confining the gafes, and again 

 immediately elevated Into the gas without being expofed to the atmofphere : and the phe- 

 nomenon could be owing to no other caufe than the Impregnation of the water with 

 atmofpheric air, becaufe when piles were plunged Into water faturated with nitrous oxide *, 



* This gas expels much conunon air from water ; fee Re/earch. Chem, & Phil, R. II. S. i. 



3 their 



