90 



Scientific Proceedings, Royal Dublin Bociety. 



packed with 25-30 grams of calcium turnings, and about 9 inches of its length at 

 the end with copper oxide to eliminate hydrogen. The gas passed from the 

 funnel through tubes eonvaiuing CaCU and ^^jd^,, bubbled through sulphuric acid, 

 and then passed over heated calcium, the issuing gas again bubbling through sul- 

 phuric acid, which served to indicate the speed of the current of gas. The gas was 

 then drawn into an automatic JSprengel pump, and delivered into a small gas- 

 holder. Before passage of the gas the apparatus was exliausted with a filter 

 pump, while the calcium tube was heated to eliminate any hydrogen evolved by 

 interaction of the calcium with any water vapour present, and finally exhausted 

 by the Sprengel pump. In all places, where possible, connections were made by 

 fusing the glass tubes together. In the few places where this was not possible 

 the rubber joints were varnished with shellac and luted with melted black rubber. 

 The exhaustion having been completed and the apparatus proved air-tight, the 

 measuring funnel was filled with gas and. adjusted to atmospheric pressure. The 

 calcium was then heated and the gas passed over slowly, the pressure in the 

 apparatus not rising above a few nims., and the residual gas being pumped off 

 continuously until exhaustion was complete. The residual gas was now passed 

 over heated copper oxide to remove hydrogen, and over phosphorus pento.xide, and 

 allowed to remain fifteen minutes in contact with charcoal immersed in liquid 

 air, which removes all gases except helium and hydrogen. The charcoal tube 

 was previously heated to 200° (J. and exhausted. From the charcoal the gas was 

 then pumped off by a Topler pump and collected for measurement. It was found 

 -that a further treatment with charcoal in liquid air did not appreciably affect 

 tlie final volume. Three estimations of the helium content were made, but the 

 other gaseous constituents were collected together in the one charcoal tube. The 

 volume of lielium was measured by passing it into a capillary tube connected with 

 a mercury reservoir, adjusting to atmospheric pressure, marking the level, subse- 

 quently tilling the space occupied by the gas with mercury, and then weighing the 

 mercury. 



The charcoal tube was now heated to 200° C, and the gases pumped off and 

 collected, when they were again passed over heated calcium and copper oxide. 

 The volume of gas remaining was then measured. On examining the spectrum of 

 this gas it showed the lines of argon strongly with some hydrogen lines. 



Results. 



The following table gives the results obtained, all volumes being reduced to 

 N.T.P. and expressed in c.cs. The argon was estimated by uniting the residual 

 gases from tlie three experiments : — 



Some determinations by other experimenters of helium and argon in natural 

 gas from other places are given for comparison, the values for nitrogen and 

 carbon-dioxide in the gas from Lucan being taken from Adeney's analysis. 



