June i i, 1896] 



NA TURE 



143 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, May 21. — " Helium and Argon. Part III. 

 Kxperimcnts which show the Inactivity of these Elements." By 

 I'rof. William Ramsay, F.R.S., and Dr. J. Norman Collie. 



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 subslancLS may be a complete 

 one. It is with this object that we place on record an account 

 of a number of experiments made to test the possibility of form- 

 ing compounds of helium and argon. 



It will be remembered that in their memoir on Argon {Phil. 

 Trans., vol. cl.xxxvi., A), Lord Rayleii^h and Prof. Ramsay 

 described numerous experiments, made in the hope of inducing 

 argon lo combine, all of w-hich yielded negative results. Two 

 further experiments have been since made— again without 

 success. 



( I ) The electric arc w'as maintained for several hours in an 

 atmosphere of argon. A slow expansion took place. 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 Cheiiiiial 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. But it 

 was thought right again to treat the g.is w ith cuprous chloride in 

 presence of ammonia, and it now ap|>eared that when left for a 

 siifticient time in contact with a strong solution, considerable 

 ctmtraction took place, carbonic oxide being removed. There 

 can, therefore, be no doubt that, althougli apparently all gas had 

 been removed from the carbon electrfjdes before admitting 

 argon, some carbon dioxide must have been still occluded, 

 probalily in the upper part of the electrodes, and that the pro- 

 longed heating due to the arc had expelled this gas and converted 

 it into monoxide. It appears, therefr>re, certain that argon and 

 carbon do not combine, even at the high temperature of the arc, 

 where any product would have a chance of escaping decompo- 

 sition by removing itself from the source of heat. It is hardly 

 necessary to point out that such a process lends itself to the 

 formation of endothermic compounds such as acetylene, and it 

 was to be supposed that if argon is capable of combination at 

 all, the resulting compound must be produced by an endothermic 

 reaction. 



(2) A product rich in barium cyanide was made by the action 

 of producer gas on a mixture of barium carbonate and carbon at 

 the intense temperature of the arc. This product was treated 

 by Dumas' process so as to recover all nitrogen ; and, as argon 

 might also have entered into combination, the nitrogen was 

 absorbed by sparking. All the nitrogen entered into combina- 

 tion with oxygen and soda, leaving no residue. Hence it may 

 be concluded that no argon enters into combination. 



(3) A mixture of argon with the vapour of carbon tetra- 

 chloride was exposed for several hours t'l a silent discharge front 

 a very powerful induction coil. The apparatus was connected 

 with a gauge which registered the pressure of the vapour of the 

 tetrachloride and of the argon of which it was mixed. Careful 

 measurement of the pressure was maile before commencing the 

 experiment, and after its completion. Although a considerable 

 amount of other chlorides of carbon was produced, no alteration 

 of pressure was noticeable ; the liberated chlorine having been 

 absorbed by the mercury present. Here again the argon did not 

 enter into the reaction, but it was recovered without loss of 

 volume. 



The remaining experiments relate to attempts to produce 

 compounds of helium. The plan of operation was to circulate 

 helium over the reagent at a bright red heat, and to observe 

 whether any alteration in volume occurred — an absorption of a 

 few c.c. could have been observed — or whether any marked 

 change was produced in the reagent employed. As a rule, after 

 the reagent had been allowed to cool in the gas, all helium was 

 removed with the pump, and the reagent was again heated to 

 redness, so as, if a compound had been formed, to decompose it 

 and expel the helium. Every experiment gave negative results ; 

 in no case was there any reason to suspect that helium had 

 entered into combination. 



A short catalogue of the substances tried may be given, none 

 of which gave any signs of combination. 



NO. 1389. VOL. 54] 



(4) Sodium. 



(5) Sihcon. 



(6) Beryllium. 



(7) Zinc. 



(S) Cadmium. 

 (9) Boron. 



(10) Yttrium. 



(11) Thallium. 



(12) Titanium. 



(13) Thorium. 



(14) Tin. 



(15) Lead. 



(16) Phosphorus. 



(17) Arsenic. 



(18) Antimony. 



(19) Bismuth. 



(20) Sulphur. 



(21) Selenium. 



(22) Uranium oxide, mixed with magnesium dust, w'as heated 

 to bright redness in helium. No change, except the reduction 

 of the oxide, took place. The mixture was allowed to cool 

 slowly in the current, and the helium was removed with the 

 pump till a phosphorescent vacuum was produced in a vacuum 

 tube communicating with the circuit. The mixture was re- 

 heated, and no helium was evolved, not even enough to show a 

 spectrum. The vacuum remained unimpaired. 



It had been hoped that elements with high atomic weight, 

 such as thallium, lead, bismuth, thorium, and uranium might 

 have effected combination, but the hope was vain. 



(23) A mixture of helium with its own volume of chlorine 

 was exposed to a silent discharge for several hours. The chlorine 

 was contained in a reservoir, sealed on to the little apparatus 

 which had the form of an ozone apparatus. No change in level 

 of the sulphuric acid confining the chlorine was detected after 

 the temperature, raised by the discharge, had again become the 

 same as that of the room. Hence helium and chlorine do not 

 combine. 



(24) Metallic cobalt in powder does not absorb helium at a 

 red heat. 



(25) Platinum black does not occlude it. 



(26) It is not caused to combine by passage over a mixture of 

 soda-lime and potassium nitrate heated to bright redness. This 

 was hardly to be expected, for it resists the action of oxygen in 

 presence of caustic soda, even when heated by the sparks which 

 traverse it. 



(27) A mixture of soda-lime and sulphur consisting of poly- 

 sulphides causes no change of volume in a current of heli um 

 passed over it at a bright red heat. 



(28) Induction sparks in an ozone apparatus passed through a 

 mixture of helium with benzene vapour in presence of liquid 

 benzene for many hours, gave no change of volume. The ben- 

 zene was, of course, altered, but the sum of the pressures of the 

 helium and the benzene-vapour remained as at first. Had helium 

 been removed, contraction would have occurred. 



This ends the catalogue of negative experiments. Any com- 

 pound of helium capable of existence would probably be endo- 

 thermic, and the two methods of producing endothermic com- 

 pounds, where no simultaneous exothermic reaction is possible, 

 are exposure to a high temperature, at which endothermic com- 

 pounds show greater stability, and the influence of the silent 

 electric discharge. These methods have been tried, so far- in 

 vain. There is, therefore, every reason to believe that the 

 elements, helium and argon, are non-valent, that is, are in- 

 capable of forming compounds. 



Chemical Society, May 21. — Mr. A. G. Vernon Harcourt, 

 President, in the chair. — The following papers were read. The 

 diphenylbenzenes, I. Metadiphenylbenzene, by F. D. Chatta- 

 way and R. C. T. Evans. Metadiphenylbenzene may be pre- 

 pared by the action of melted sodium on a boiling xylene 

 solution of metadichlorobenzene and chlorobenzene ; it melts at 

 84°. — Derivatives of camphoric acid, by F. S. Kipping. A 

 lactonic monocarboxylic acid, C,(,H,j04, which the author terms 

 trans-ir-camphanic acid, is obtained by boiling sodium T-bromo- 

 camphorate with water ; its cis-isomeride can only be prepared 

 as a salt. On oxidising trans-7r-camphanic acid, transcampho- 

 tricarboxylic acid CjoHijO^ is obtained ; on fusion with potash 

 it yields the isomeric ciscamphotricarboxylic acid. — On some 

 substances which exhibit rotatory power both in the liquid and 

 crystalline states, by W. J. Pope. Cis-ir-camphanic acid and 

 transcamphotricarboxylic acid possess the power of circularly 

 polarising light, both in the dissolved and crystalline state ; in 

 the former case the circular polarisation in the crystalline state 

 is a specific property of the crystalline structure, but in the latter 

 it is due to complicated twinning of the crystals. — Dimethoxy- 

 diphenylmethane and some of its homologues, by J. E. 

 Mackenzie. Dimethoxydiphenylmethane, and the correspond- 

 ing diethoxy- and dibenzoxy-compounds, may be prepared by 

 the interaction of benzophenone chloride and the sodio-derivative 

 of methylic, ethyUc or benzylic alcohol respectively. 



