M. Pouillet on the Electricity of Elastic Fluids. 49 



visit its philosophers. Among the remarkable inventions by 

 which he was distinguished, that of the condenser was then the 

 most recent, and excited the liveliest interest. This instrument 

 could not fail to be well received and appreciated by the Aca- 

 demy of Sciences in Paris ; and indeed two of the most illustri- 

 ous members of that body, MM. Lavoisier and La Place, 

 had hardly become acquainted with the instrument, when they 

 consecrated its immense utility by a great discovery. The} 

 saw for the first time, in concert with Volta, that in chemical 

 combinations electricity is developed, and that, by means of the 

 condenser, it can be collected and rendered sensible. These 

 experiments, which opened up a new career, have been since re- 

 peated with various success. Volta relates in his works, that 

 he never failed to obtain electricity by the evaporation of wa- 

 ter, and by the combustion of charcoal. De Saussure, on the 

 contrary, who made such exact and curious experiments on 

 the formation of vapour, never succeeded in obtaining elec- 

 tricity by combustion. Neither could Sir H. Davy discover 

 any trace of electricity by the combustion of iron or of charcoal 

 in pure oxygen or in air. More recently other natural philo- 

 sophers have made new inquiries upon the electricity of flame, 

 but their hypotheses have not led them to the truth*. 



The fundamental result to which I have arrived explains 

 very simply these contradictions and these errors. In repeat- 

 ing these experiments, I applied myself, in the first place, to the 

 combustion of charcoal, and, in my first attempt, I saw with 

 great surprise, that one could draw from it sometimes positive 

 electricity, sometimes negative, and that at other times there 

 was no means of obtaining the slightest signs of electricity. 

 From these different and even opposite results, it appears at 

 first that there is nothing to be deduced ; but upon reflection, 

 we see for certain that the combustion of charcoal gives elec- 

 tricity ; for if it did not give any, it could not have been ob- 

 served. Besides it is clear that it gives the two electricities, 

 since sometimes the resinous and sometimes the vitreous has 

 been obtained. Supposing, then, that one of the electricities 

 is taken by the charcoal, and the other by the oxygen or by 



• Ann. de Chim. torn. xxv. p. 378, xxvi.i, p. 5. 

 NEW SERIES. VOL. I. NO. I. JULY 1829< Pk 



