56 DR. FARADAY'S EXPERIMENTAL RESEARCHES IN ELECTRICITY. 



567. It was found, by various experiments, that this effect was not due to the escape 

 or solution of the gas, nor to recombination of the oxygen or hydrogen in consequence 

 of any peculiar condition they might be supposed to possess under the circumstances ; 

 but to be occasioned by the action of one or both of the poles within the tube upon 

 the gas around them. On disuniting the poles from the pile after they had acted 

 upon dilute sulphuric acid, and introducing them into separate tubes containing mixed 

 oxygen and hydrogen, it was found that the positive pole effected the union of the 

 gases, but the negative pole apparently not (588.). It was ascertained also that no 

 action of a sensible kind took place between the positive pole with oxygen or hydrogen 

 alone. 



568. These experiments reduced the phenomena to the consequence of a power 

 possessed by the pJatina, after it had been the positive pole of a voltaic pile, of causing 

 the combination of oxygen and hydrogen at common, or even at low, temperatures. 

 Tliis effect is, as far as I am aware, altogether new, and was immediately followed 

 out to ascertain whether it was really of an electric nature, and how far it would in- 

 terfere with the determination of the quantities evolved in the cases of electro-che- 

 mical decomposition required in the fourteenth section of these Researches. 



569. Several platina plates were prepared (fig. 2.). They were nearly half an 

 inch wide, and two inches and a half long : some were ^^odth of an inch, others not 

 more than 7-^xjdth, and some were as much as y^jth of an inch in thickness. Each had 

 a piece of platina wire, about seven inches long, soldered to it by pure gold. Then a 

 number of glass tubes were prepared : they were about nine or ten inches in length, 

 fths of an inch in internal diameter, were sealed hermetically at one extremity, and 

 were graduated. Into these tubes was put a mixture of two volumes of hydrogen and 

 one of oxygen, at the water pneumatic trough, and when one of the plates described 

 had been connected with the positive or negative pole of the voltaic battery for a given 

 time, or had been otherwise prepared, it was introduced through the water into the 

 gas within the tube ; the whole set aside in a test-glass (fig. 3.), and left for a longer 

 or shorter period, that the action might be observed. 



570. The following result may be given as an illustration of the phenomenon to be 

 investigated. Diluted sulphuric acid, of the specific gravity 1-336, was put into a 

 glass jar, in which was placed also a large platina plate, connected with the negative 

 end of a voltaic battery of forty pairs of four-inch plates, with double coppers, and 

 moderately charged. One of the plates (569.) was then connected with the positive 

 extremity, and immersed in the same jar of acid for five minutes, after which it was 

 separated from the voltaic battery, washed in distilled water, and introduced through 

 the water of the pneumatic trough into a tube containing the mixture of oxygen and 

 hydrogen (569.). The volume of gases immediately began to lessen, the diminution 

 proceeding more and more rapidly until about f ths of the mixture had disappeared. 

 The upper end of the tube became quite warm, the plate itself so hot that the water 

 boiled as it rose over it ; and in less than a minute a cubical inch and a half of the 



