h\j Means o/'Doebereiner's Eudiometer. 277 



4tlily. Cyanogen, similarly treated, was not changed at a tem- 

 perature of 555° Fahrenheit ; and on applying the flame of a 

 spirit lamp to the tube, it produced no action till the tube ber 

 gan to soften. 



5thly. Muriatic acid gas, mixed with half its volume of oxy- 

 gen, began to be acted upon at 250° Fahrenheit. Water was 

 evidently formed ; and the disengaged chlorine, acting upon 

 the mercurial vapour in the tube, formed calomel, which was 

 condensed, and coated its inner surface. 



6thly. Ammoniacal gas, mixed with an equal volume of oxy- 

 gen, showed a commencement of decomposition at 380° Fah- 

 renheit. Water was also in this case distinctly generated ; 

 and at the close of the experiment nothing remained in the 

 tube but nitrogen and the redundant oxygen. 



I proceeded, in the next place, to examine the agency of 

 finely-divided platinum at high temperatures, on those mix- 

 tures of gases, which are either not decomposed, or are slowly 

 decomposed, at the temperature of the atmosphere. 



When carbonic oxide and hydrogen gases, in equal volumes, 

 mixed with oxygen suflicient to saturate only one of them, 

 were placed in contact with the sponge, and gradually heated 

 in a mercurial bath, the mixture ceased to expand between 

 300° and 310° Fahrenheit, and soon began to diminish in vo- 

 lume. On raising the temperature to 340°, and keeping it 

 some time at that point, no further diminution was at length 

 perceptible. From the quantity of carbonic acid remaining 

 at the close of the experiment, it appeared that four-fifths of 

 the oxygen had united with the carbonic oxide, and only one- 

 fifth with the hydrogen. When four volumes of hydrogen, 

 two of carbonic oxide, and one of oxygen, were similarly treat- 

 ed, the hydrogen, notwithstanding its greater proportional vo- 

 lume, was still found to have taken only one-fifth of the oxy- 

 gen, while four-fifths had combined with the cai'bonic oxide. 

 These facts show that at temperatures between 300° and 

 340° Fahrenheit, the affinity of carbonic oxide for oxygen is 

 decidedly superior to that of hydrogen ; as, from the experi- 

 ments before described, appears to be the case, also, at com- 

 mon temperatures. 



But a similar distribution of oxygen, between carbonic oxide 

 and hydrogen, does not take place, when those three gases 

 are fired together by the electric spark. This will appear from 

 the following table, in which the three first columns show the 

 quantities of gases that were fired, and the two last, the quan- 

 tities of oxygen that were found to have united with the car- 

 bonic oxide and with the hydrogen. 



Exp. 



