18:35.] Alexander Volta. 83 



that a given body, whether empty or full, possesses the elec- 

 trical capacity, provided the surface remains constant. The 

 experiments of Volta, however, shewed that of two cylinders, 

 possessing the same surface, the longest receives the greatest 

 charge, so that an immense advantage is gained by substitut- 

 ing for the large conductors of common machines, a system 

 of very small cylinders, although on the whole, these do not 

 occupy a greater bulk. In combining for example, sixteen 

 wires of thin plated rods, each 1000 feet in length, according 

 to Volta a machine would be produced whose sparks would 

 kill the largest animal. 



None of Volta's discoveries were fortuitous. All the 

 instruments with which he enriched science were fairly 

 planned out in his imagination before the artist was em- 

 ployed to construct them. 



In 1776 and 1777, the professor of Como was occupied 

 with purely chemical subjects. At this time chemists 

 considered that inflammable gas was a product of coal and 

 salt mines only, but Volta proved that the putrifaction of 

 animal and vegetable substances is always accompanied 

 with the disengagement of inflammable gas, and that if we 

 stir the bottom of stagnant pools, the gas escapes, producing 

 all the appearances of ebullition. Thus, the carburetted 

 hydrogen of marshes was first discovered by Volta. 



He ascribed burning mountains and formations to the 

 same cause; and in 1780, visiting Pietra Mala de Velleja, 

 he proved that the phenomenon so celebrated at that place 

 was owing, not to petroleum or naphtha, but to carburetted 

 hydrogen. The electric spark was used to set fire to certain 

 liquids, vapours, and gases, such as alcohol, the smoke of a 

 newly extinguished candle, and hydrogen, but all these expe- 

 riments were made in the open air. Volta was the first who 

 repeated them in close vessels, in 1777, and to him there- 

 fore, is to be ascribed the idea of the apparatus in which, 

 in 1781 , Cavendish synthetically formed water by combining 

 the two constituent gases by means of the electric spark. 

 \ Volta never abandoned a subject until he had considered 

 it in all its branches, uniting in a remarkable manner, the 

 unusual combination of an inventive genius, and the spirit 

 of application. Thus, in his researches upon inflammable 

 gas, he discovered the electrical gun and pistol, then the 



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