554 SPECIAL METHODS OF DISCOVERY. 



same investigators discovered that the human body, is a 

 conductor; that sulphur, resins, &c., when melted and 

 allowed to cool upon insulators, were electric ; and that 

 electricity may be retained in bodies by wrapping them 

 in worsted. By applying the electric force to the head 

 of a recently killed ox, Aldini in 1796 discovered thai 

 powerful muscular contractions were produced. By pass- 

 ing electric sparks through a mixture of oxygen and 

 hydrogen, Fourcroy, Vauquelin, and Seguin in 1790 dis 

 covered the qualitative composition of water synthetically, 

 and in the same year, by passing the electric spark, by 

 means of fine gold wires, as electrodes, through water, 

 Paetz and Van Troostwik discovered the electric decom- 

 position of water. By means of voltaic electricity, in the 

 year 1800, Cruickshank discovered the effect of that force 

 on litmus paper, and Dr. Henry decomposed nitric and 

 sulphuric acids. 



It was by applying the voltaic current to various sub- 

 stances in a similar way to that in which Nicholson and Car- 

 lisle had applied it to water that ' Henry, Haldane, Davy, 

 and other experimenters found that other chemical com- 

 pounds were decomposed by the electric currents as well 

 as water. Ammonia, for example, nitric acid, and various 

 salts were decomposed by it. In the year 1803, an im- 

 portant set of experiments was published by Berzelius and 

 Hisinger. They decomposed eleven different salts by 

 exposing them to the action of a current of electricity. 

 The salts were dissolved in water, and iron or silver wires 

 from the two poles of the pile were plunged into the solu- 

 tion. In every one of these decompositions the acid was 

 deposited round the positive wire, and the base of the salt 

 round the negative wire. When ammonia was decom- 

 posed by the action of galvanic electricity, the azotic gas 

 separated from the positive wire, and the hydrogen from 



