

Helium and Argon, their Inactivity. 53 



" Helium and Argon. Part III. Experiments which show 

 the Inactivity of these Elements." By WILLIAM RAMSAY, 

 Ph.D., F.R.S., and J. NORMAN COLLIE, Ph.D., F.R.S.E. 

 Received April 22, Read May 21, 1896. 



To chronicle a list of failures is not an agreeable task ; and yet it 

 is sometimes necessary, in order that the record of the behaviour of 

 newly discovered substances may be a complete one. It is with this 

 object that we place on record an account of a number of experiments 

 made to teat the possibility of forming compounds of helium and 

 argon. 



It will be remembered that in our memoir on Argon,* Lord 

 Rayleigh and Professor Ramsay described numerous experiments, 

 made in the hope of inducing argon to combine, all of which 

 yielded negative results. Two further experiments have been since 

 made again without success. 



1. The electric arc was maintained for several hours in an atmo- 

 sphere of argon. The electrodes were thin pencils of gas carbon, 

 and, previous to the introduction of the argon, the arc was made 

 in a vacuum, and all gas evolved was removed by pumping. Argon 

 was then admitted up to a known pressure, and the arc was again 

 made. A slow expansion took place ; one of the electrodes di- 

 minished in length, and the bulb became coated with a black deposit. 

 The resulting gas was treated with caustic soda and with a solution 

 of ammoniacal cuprous chloride, and, on transference to a vacuum- 

 tube, it showed the spectrum of argon along with a spectrum 

 resembling that of hydrocarbons. Having to leave off work at this 

 stage, a short note was sent to the * Chemical News ' on a Possible 

 Compound of Argon. On resuming work after the holidays, the gas 

 was again investigated, and, on sparking with oxygen, carbon dioxide 

 was produced. Bat it was thought right again to treat the gas with 

 cuprous chloride in presence of ammonia, and it now appeared that 

 when left for a sufficient time in contact with a strong solution, 

 considerable contraction took place, carbonic oxide being removed. 

 There can, therefore, be no doubt that, although apparently all gas 

 had been removed from the carbon electrodes before admitting argon, 

 some carbon dioxide must have been still occluded, probably in the 

 upper part of the electrodes, and that the prolonged heating due to 

 the arc had expelled this gas and converted it into monoxide. It 

 was, indeed, inexplicable how an expansion should have taken place 

 unless by some such means; for the combination of a monatomic 

 gas must necessarily be accompanied by contraction. It appears, 

 therefore, certain that argon and carbon do not combine, even at 

 * < Phil. Trans.,' vol. 186, A. 



