SCIENCE. 



[N. S. Vol. VIII. No. 183. 



lecting the gas from that small residue in a 

 gas holder, we obtained, after removal of 

 oxygen with metallic copper and nitrogen 

 with a mixture of pure lime and magnesium 

 dust, followed by exposure to electric sparks 

 in presence of oxygen and caustic soda, 

 26.2 cubic centimeters of a gas, showing the 

 argon spectrum feebly, and, in addition, a 

 spectrum which has, we believe, not been 

 seen before. 



We have not yet succeeded in disentang- 

 ling the new spectrum completely from the 

 argon spectrum, but it is characterized by 

 two very brilliant lines, one almost identi- 

 cal in position with D,, and almost rivalling 

 it in brilliancy. Measurements made with 

 a grating of 14,438 lines to the inch, kindly 

 placed at our disposal by Mr. E. 0. C. Baly, 

 gave the following numbers, all four lines 

 heing in the field at once : 



Di 5895.0 



Dj 5889.0 



D3 5S75.9 



D4 5866.65 + 1-7 to correct to vacuum. 



There is also a green line, comparable 

 with the green helium line in intensity, 

 of wave-length 5566.3, and a somewhat 

 weaker green, the wave-length of which is 

 5557.3. 



In order to determine, as far as possible, 

 which lines belong to the argon spectrum, 

 and which to the new gas, both spectra 

 were examined at the same time with the 

 grating, the first order being employed. 

 The lines which were absent, or very fee- 

 ble, in argon have been ascribed to the new 

 gas. Owing to their feeble intensity, the 

 measurements of the wave-lengths which 

 follow must not be credited with the same 

 degree of accuracy as the three already 

 given, but the first three digits may be 

 taken as substantially correct : 

 Violet 



Mr. Baly has kindly undertaken to make 

 a study of the spectrum, which will be 

 published when complete. The figures al- 

 ready given, however, suffice to character- 

 ise the gas as a new one. 



The approximate density of the gas was 

 determined by weighing it in a bulb of 

 32.321 cubic centimeters' capacity, under a 

 pressure of 521.85 millimeters, 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 millimeters, 

 and temperature was 16.45°. The weight 

 was 0.04228 gram, which implies the den- 

 sity 22.51. 



The wave-length of sound was deter- 

 mined in the gas by the method described 

 in the ' Argon ' paper. The data are : 



Wave-len£>;th in air 



34.17 



29.87 



34.30 

 30.13 



Calculating by the formula 



/i^air X density air : A^gas X deUSitygas : : J'air : )'b>s 



(34.33)2X14.479 : (30)2 ^ 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 con- 

 cluded that the atmosphere contains a 

 hitherto undiscovered gas with a character- 

 istic 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 pro- 

 pose to call it ' krypton,' or ' concealed.' Its 

 symbol would then be Kr. 



It is, of course, impossible to state posi- 

 tively what position in the periodic table 

 this new constituent of our atmosphere will 



