48 M. Pouillet o?i the Electricity of Elastic Fluids. 



and to combat it now we must bring very decisive and direct 

 proofs. 



In repeating the experiments by which the ablest observers 

 have supposed it proved that changes in the condition of 

 bodies are attended with a disengagement of electricity, it 

 has happened to me, that the electrical signs have been so 

 much weaker the more pains I took to avoid these foreign 

 causes. For instance, when I took water perfectly pure to 

 make it evaporate, either slowly or rapidly, upon a body which 

 could not combine either with itself or with its elements, it was 

 impossible to collect the least signs of electricity. 



From numerous experiments made upon different bodies, I 

 find that it is not the change of condition which disengages elec- 

 tricity, but always a chemical action more or less vigorous, which 

 exerts itself between the elements of these bodies and the ves- 

 sels which contain them ; for by avoiding these chemical ac- 

 tions, every trace of electricity diappears. 



As the origin of the electricity of the air, therefore, cannot 

 be that which Volta has assigned, I have been induced, with 

 some confidence, to suppose another origin which I have 

 thought of for a long time past. 



It appears to me that the phenomena of vegetation cannot 

 be accomplished without a disengagement of electricity, and 

 experience has, in fact, confirmed this idea in the most striking 

 manner. 



But before undertaking direct experiments upon vegetable 

 actions, which must necessarily be very delicate and complicat- 

 ed, it is necessary to examine the electric properties of the 

 erases at the moment of their combination. 



o 



This paper, therefore, will be divided into two parts. The 

 first relative to the electricity of the gaseous combinations, and 

 the second to the electricity which is developed in vegetation. 



Part I. 



On the Electricity of Gaseous Combinations. 



The first discoveryof the developement of electricity by chemi- 

 cal action was made in 1781. At that time Volta was in Paris. 

 Already celebrated in Italy, he had travelled over all Europe to 



