1835.] Alexander Volta. 87 



and of certain combinations of the electrometer and con- 

 denser. This letter is well worthy the attention of young 

 philosophers. 



In 1785Saussure increased the delicacy of the electrometer, 

 by the simple addition of a stalk, eight or nine decimetres 

 in length. And Volta in 1787, further added to its sensi- 

 bility, by adapting to the metallic addition of Saussure a 

 lighted candle, or even a match. He even suggested that, 

 from the excellent electrical conducting power of flame, 

 the best method of preventing the evil effects of thunder 

 storms, would be to make large fires in the midst of plains, 

 or on the summit of elevated places. His views have not 

 hitherto been subjected to the test of experiment. Perhaps 

 some light might be thrown on the subject by comparing 

 the meterological observations of those localities where 

 iron-works are established with the surrounding agricultural 

 districts. The learned endeavoured, not from a wish to 

 honour the dead, to show that his discovery had been anti- 

 cipated by the ancients, and considered that the fabulous 

 Greek fires were to be ascribed to this cause. 



The hypothesis which had been formed that the electric 

 phenomena are attributable to two fluids, naturally con- 

 ducted to the investigation of the source from which they 

 emanate. A simple experiment tended to solve the question. 

 A vessel insulated where water was evaporating gave evident 

 proofs of negative electricity. • 



It is not well known to whom the merit of this experiment 

 is to be ascribed. Volta in one of his memoirs says, that 

 he had thought of it in 1778, but that different circumstances 

 having prevented him from executing it, he only succeeded 

 at Paris in March 1780, in company with some members of 

 the Academy of Sciences. On the other hand, Lavoisier 

 and Laplace merely say that Volta wished to assist at their 

 experiment, and to be useful to them. The cause of this 

 difference in their statements is that Volta was present at 

 the first experiment, which did not succeed, but was absent 

 from the successful one. He, however, planned the means 

 of discovery and the actual experiment, and is entitled to 

 the credit of the success. According to him, when the 

 insulated metallic vessel in which water is evaporating 

 becomes electrical, the water, .in order to pass into the 



