COMBINATION OF OXYGEN AND HYDROGEN BY PLATINA POLES. 57 



gases were gone, having been combined by the power of the platina, and converted 

 into water. 



571. This extraordinary influence acquired by the platina at the positive pole of 

 the pile, is exerted far more readily and effectively on oxygen and hydrogen than on 

 any other mixture of gases that I have tried. One volume of nitrous gas was mixed 

 with a volume of hydrogen, and introduced into a tube with a plate which had been 

 made positive in the dilute sulphuric acid for four minutes (570.). There was no sen- 

 sible action in an hour : being left for thirty-six hours, there was a diminution of about 

 one eighth of the whole volume. Action had taken place, but it had been very feeble. 



572. A mixture of two volumes of nitrous oxide with one volume of hydrogen was 

 put with a plate similarly prepared into a tube (569. 570.). This also showed no 

 action immediately ; but in thirty-six hours nearly a fourth of the whole had disap- 

 peared, i. e. about half of a cubic inch. By comparison with another tube containing 

 the same mixture without a plate, it appeared that a part of the diminution was due 

 to solution, and another part to the power of the platina ; but the action had been 

 very slow and feeble. 



573. A mixture of one volume olefiant gas and three volumes oxygen was not af- 

 fected by such a platina plate, even though left together for several days (G40. 641.). 



574. A mixture of two volumes carbonic oxide and one volume oxygen was also 

 unaffected by the prepared platina plate in several days (645. &c.). 



575. A mixture of equal volumes of chlorine and hydrogen was used in several 

 experiments, with plates prepared in a similar manner (570.). Diminution of bulk 

 soon took place ; but when after thirty-six hours the experiments were examined, 

 it was found that nearly all the chlorine had disappeared, having been absorbed, prin- 

 cipally by the water, and that the original volume of hydrogen remained unchanged. 

 No combination of the gases, therefore, had here taken place. 



576. Reverting to the action of the prepared plates on mixtures of oxygen and 

 hydrogen (570.), I found that the power, though gradually diminishing in all cases, 

 could still be retained for a period varying in its length with circumstances. When 

 tubes containing plates (569.) were supplied with fresh portions of mixed oxygen and 

 hydrogen as the previous portions were condensed, the action was found to continue 

 for above thirty hours, and in some cases slow combination could be observed even 

 after eighty hours ; but the continuance of the action greatly depended upon the 

 purity of the gases used (638.). 



577. Some plates (569.) were made positive for four minutes in dilute sulphuric 

 acid of specific gravity 1*336 : they were rinsed in distilled water, after which two were 

 put into a small bottle and closed up, whilst others were left exposed to the air. The 

 plates preserved in the limited portion of air were found to retain their power after 

 eight days, but those exposed to the atmosphere had lost their force almost entirely in 

 twelve hours, and in some situations, where currents existed, in a much shorter time. 



578. Plates were made positive for five minutes in sulphuric acid, specific gra- 



MDCCCXXXIV. I 



