54 Drs. W. Ramsay and J. Norman Collie. 



the high temperature of the arc, where any product would have a 

 chance of escaping decomposition 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 combination with oxygen and soda, 

 leaving no residue. Hence it may be concluded that no argon 

 enters into combination. For the successful carrying out of these 

 experiments we have to thank Mr. G. W. MacDonald. 



3. A mixture of argon with the vapour of carbon tetrachloride 

 was exposed for several hours to a silent discharge from a very 

 powerful induction coil. The apparatus was connected with a 

 gauge which registered the pressure of the vapour of the tetra- 

 chloride and of the argon of which it was mixed. Careful measure- 

 ment of the pressure was made 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 com- 

 pounds 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 pro- 

 duced 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 com- 

 pound 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. 



4. Sodium distilled in the current of gas, and condensed in drops 

 with bright metallic lustre. The glass tube in which it was heated 

 became covered with a coating of 



5. Silicon, which caused no absorption. 



6. A mixture of beryllium oxide and magnesium, yielding metallic 

 beryllium, was without action. 



