On a new Constituent of Atmospheric Air. 407 



Mr. Baly has kindly undertaken to make a study of the spectrum, 

 which will be published when complete. The figures already given, 

 however, suffice to characterise the gas as a new one. 



The approximate density of the gas was determined by weighing 

 it in a bulb of 32*321 cubic centimetres capacity, under a pressure of 

 521*85 millimetres, and at a temperature of 15*95. The weight of 

 this quantity was 0*04213 gram. This implies a density of 22*47, 

 that of oxygen being taken as 16. A second determination, after 

 sparking for four hours with oxygen in presence of soda, was made in 

 the same bulb ; the pressure was 523' 7 millimetres, and the tempera- 

 ture was 16*45. The weight was 0*04228 gram, which implies the 

 density 22*51. 



The wave-length of sound was determined in the gas by the 

 method described in the " Argon " paper. The data are : 



i. ii. iii. 



Wave length in air 34*17 34*30 34*57 



,, gas 29*87 30*13 



Calculating by the formula 



X 2 air X density air : \ 2 gas X density gas : : 7 air : <y gas) 

 (34*33) 2 x 14*479 : (30) 3 x 22*47 : : 1*408 : 1*666, 



it is seen that, like argon and helium, the new gas is monatomic and 

 therefore an element. 



From what has preceded, it may be concluded that the atmo- 

 sphere contains a hitherto undiscovered gas with a characteristic 

 spectrum, heavier than argon, and less volatile than nitrogen, oxygen, 

 and argon ; the ratio of its specific heats would lead to the inference 

 that it is monatomic, and therefore an element. If this conclusion 

 turns out to be well substantiated, we propose to call it " krypton," 

 or " hidden." Its symbol would then be Kr. 



It is, of course, impossible to state positively what position in the 

 periodic table this new constituent of our atmosphere will occupy. 

 The number 22*51 must be taken as a minimum density. If we may 

 hazard a conjecture, it is that krypton will turn out to have the 

 density 40, with a corresponding atomic weight 80, and will be found 

 to belong to the helium series, as is, indeed, rendered probable by 

 its withstanding the action of red-hot magnesium and calcium on 

 the one hand, and on the other of oxygen in presence of caustic 

 soda, under the influence of electric sparks. We shall procure a 

 larger supply of the gas, and endeavour to separate it more com- 

 pletely from argon by fractional distillation. 



It may be remarked in passing that Messrs. Kayser and Fried- 

 lander, who supposed that they had observed D 3 in the argon of the 



