56 Mr Pouillet cm the Electricity of Elastic Fluids. 



Part II. 



On the Electricity produced by Vegetables. 



After having ascertained as far as was in my powef the 

 truth and fertility of the principle I have now announced, 

 saw the possibility of applying it to the combinations which 

 operate in nature, and especially to those which are incessantly 

 produced by the leaves of vegetables with atmospheric air. 

 We know by the experiments of Priestley, Ingenhouz, and 

 Sennebier, and above all, by the accurate and ingenious in- 

 quiries of Mr. Theod. de Saussure, that the various parts of 

 plants act upon atmospheric air ; that sometimes they form, at 

 the expence of the oxygen, a large enough quantity of carbo- 

 nic acid, which disengages itself insensibly ; and that they some- 

 times exhale the oxygen pure, proceeding from some combina- 

 tion which takes place in the interior of the plant. 



But if it is true that all carbonic acid is electrified vitreously 

 at the moment of its formation, it follows that the plants ought 

 to produce in the air by the exhalation of this acid, a quan- 

 tity of vitreous electricity more or less considerable. This was 

 the chief object of my researches ; and 1 was very impatient for 

 the fine weather to arrive, to prove this result, which appeared 

 to me a necessary one. Since the month of March, I have 

 made in my laboratory a sufficient number of experiments to 

 show that vegetation is an abundant source of electricity ; and 

 consequently, a powerful cause to produce atmospheric electri- 

 city. My experiments were made in the following manner : — 



Twelve capsules of glass from 8 to 10 inches in diameter, 

 are coated externally, and only towards the edge, to a distance 

 of one or two inclies, with a film of gum lac varnish. They 

 are arranged in two rows beside one another, either by placing 

 them simply upon a table of very dry wood, or by putting 

 them upon a table itself varnished with gum lac. They are 

 filled with vegetable mould, and they are made to communicate 

 with each other by metallic wires, which go from the interior of 

 the one to the exterior of the other, passing over the edges of the 

 capsules. Then all the insides of the twelve capsules, and the 

 mould which they hold, form but one conducting body. Sup- 

 pose that frcm any cause whatever electricity is communicated 



