﻿210 Prof. W. Ramsay on the Passage of 



Account of Experiments. 



The experiments admit of classification under five heads: — 



1. Experiments with the tube filled with air. 



2. Experiments with the tube filled with nitrogen. 



3. Experiments in which the hydrogen passed over the 

 exterior of the tube was diluted with nitrogen or other gases, 

 when it exercised only a partial pressure on the exterior 

 walls of the tube. 



4. Experiments in which the palladium tube was filled with 

 other gases. 



5. Experiments with a nickel tube and carbon monoxide. 

 Experiment 1. — The tube was filled with air and jacketed 



with bromonaphthalene, boiling at about 280°. The baro- 

 metric pressure during the experiment was constant at 743' 1 

 millim. On passing hydrogen for three hours the pressure in 

 the palladium cell had become constant ; the rise of pressure 

 was 573 millim. 



"Water appeared on the surface of the mercury in the capil- 

 lary tube, showing that the hydrogen had combined with the 

 oxygen of the air. The rise of pressure measured should 

 therefore have been that of the nitrogen remaining in the 

 cell, viz 585 millim. 



It may be concluded, then, that hydrogen combines with 

 oxygen in presence of palladium at 280°, and that the residual 

 nitrogen exerts nearly its partial pressure ; or, as wall be 

 afterwards shown to be a more correct statement, the nitrogen 

 exerts its full partial pressure, and the hydrogen in the interior 

 exerts a large fraction of the pressure of the external hydrogen. 



Experiment 2. — The tube was filled with pure dry nitrogen, 

 and exposed to hydrogen, as before, at the same temperature. 

 The pressure, after it had become fairly steady, was 703*2 

 millim. in excess of that of the atmosphere (748*1 millim.). 

 The hydrogen was next removed by passing a current of air 

 over the exterior of the tube, and the pressure was again 

 raised by a current of hydrogen. After about three-quarters 

 of an hour the pressure was 699*8 millim. in excess of that of 

 the atmosphere, a quarter of an hour later it was 721*1 millim., 

 and in another quarter of an hour it had risen to 733*0 millim. 

 It appeared then to be stationary. The barometric pressure 

 was still 748*1 millim.; it therefore appears that the pressures 

 of the hydrogen on the exterior and interior of the palladium 

 tube were nearly equal. 



It was noticed during these experiments that when the gas 

 was changed the pressure invariably fell a little on admitting 

 hydrogen and rose a little on admitting oxygen ; the^direction 



