276 RECENTLY DISCOVERED GASES. 



density of pure argon arises from the fact that the neon,, which is the 

 chief impurity present, has been removed ; the influence of the other 

 gases can not be recognized, owing to the insignificant quantities 

 present. In fact, in 15 liters of argon we found no appreciable trace of 

 xenon; it can be prepared only out of large quantities of liquid air. 



I must take this opportunity of thanking you most sincerely for the 

 honor you have done me in inviting me to deliver this address. It has 

 been said by some scientist that the greatest joy of life lies in discover- 

 ing something which is new. There is, however, another joy almost 

 equally great, that of making known the results of an investigation to 

 one's fellow-scientists. This joy, my friends, you have given me to an 

 extreme degree, and for this I express to you my warmest thanks. 



