88 Scientific Intelligence. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. The Higher Layers of the Atmosphere. — Alfred Wegener 

 has given an interesting discussion of this subject, upholding the 

 view that there are higher strata of the earth's atmosphere of 

 entirely different composition from that of the lower atmosphere. 

 As long ago as 1875 Harm concluded from a theoretical consider- 

 ation of the laws of gases that the upper atmosphere must con- 

 sist of pure hydrogen, if this gas, as supposed, was a constituent 

 of the air. In 1903, after the work of Gamier had indicated the 

 probable presence of a minute quantity of hydrogen in the air, 

 Hann made further calculations and reached the conclusion that 

 at a height of 50 km. the air would contain 14 percent by volume 

 of hydrogen, while at 100 km. there would be 99 per cent of it. 

 Somewhat later Wegener expressed the view that at a height of 

 70-80 km. there must be a sudden change in density of the atmos- 

 phere for the reason that Krakatoa clouds stopped at this height, 

 and that this is the limit at which diffuse reflection of light is 

 observed. Afterwards he made calculations similar to Hann's 

 and found, by using smaller intervals of height, that there was 

 theoretically a sudden change in composition at exactly the same 

 altitude at which he was led to assume a limiting layer for other 

 reasons. He called attention to the analogy between such a 

 sharply limited hydrogen atmosphere, surrounding the earth, to 

 the well-known hydrogen atmosphere of the sun's chromosphere, 

 and he advanced the view that above the hydrogen layer there 

 might be found another stratum of a still lighter gas correspond- 

 ing to the coronium of the sun. This supposition of a higher 

 layer is based upon the position of the highest northern lights, 

 which like coronium give a green spectrum line, although these 

 lines are different. 



Another argument in favor of a distinct, higher stratum of the 

 atmosphere has been brought forward in connection with the 

 highly remarkable sound phenomena that occurred in connection 

 with the great dynamite explosion at the Jungfrau railroad on 

 November 15th, 1908. There was a normal region of audibility 

 extending about 40 km. and immediately surrounding the place 

 of explosion ; then there was a second, abnormal, and much more 

 extensive, region of sound, which was separated from the first 

 region by a "zone of silence" about 100 km. wide. While this 

 phenomenon was at first attributed to a change in wind at a high 

 altitude, the hypothesis was advanced by v. dem Borne that it 

 was due to a reflection of the sound-waves upon the higher 

 hydrogen layer of the atmosphere, and his calculations showed 

 that this view was very plausible in connection with the facts of 

 the case. 



