TEE METEOROLOGY OF THE FUTURE 27 



nature analogous to that of a resisting gas. In fact, as the meteors are 

 burned up, we must acknowledge that the debris are perpetually making 

 new additions to our atmosphere. So important is this question, both to 

 astronomy and to meteorology, that the Astronomical and Astrophys- 

 ical Society of America has lately started an inquiry as to what meth- 

 ods are available for photographing meteors and meteor trains, or what 

 studies can give us any facts about the highest air. I understand Pro- 

 fessor Woodward to state that there is a mechanical possibility of the 

 existence of another atmosphere above that which affects our barometer, 

 which therefore may revolve about the globe, like the rings of Saturn, 

 in equilibrium within itself. 



The most interesting definite problem bearing on the highest at- 

 mosphere relates to the cause and nature of the aurora borealis. These 

 beautiful northern lights have been carefully studied by Swedes and 

 Norwegians. Twenty years ago, all the nations of the globe united in a 

 series of expeditions to both the arctic and antarctic regions for the 

 study of magnetism, auroras and meteorology. Since that date four 

 special expeditions have been sent northward by Norwegians, and the 

 leader of these. Professor Birkeland, of Christiania, has developed some 

 new views as to the aurora, that have been confirmed by the mathe- 

 matical investigations of his colleague. Professor Stoermer. They have 

 devised remarkable ways of continuous photography and accurate cal- 

 culation of altitudes.^ The publication of the details of their work has 

 begun, and I think we may safely anticipate that future generations will 

 busy themselves developing the ideas that are now being presented by 

 these physicists. All that we need say at the present moment is that 

 particles which we call ions (or, when they are electrified, electrons), 

 pass with the velocity of light from the sun to the earth. If this be 

 incredible, we must at least say that some influence passes from the sun 

 to the earth, with the speed of gravity or the speed of light, causing 

 electrons from space or from the celestial bodies to approach the earth's 

 atmosphere with great speed. But no sooner do these come within the 

 influence of the earth's magnetism (and that influence extends to great 

 distances beyond the atmosphere), no sooner do the electrons feel this 

 influence, than they are diverted from their straight-line courses and 

 begin to describe curves surrounding the earth like spiral corkscrews. 

 Whenever such particles enter certain gases (such as krypton), the gas 

 becomes luminescent or phosphorescent, and gives us the auroral light. 

 This hypothesis is sufficiently complex to allow of many uncertainties as 

 to details. It is at present in its formative stage, but there is good 

 reason to believe that we have here a solid base on which to build a 

 structure that will carry us from the firm ground of experimental lab- 

 oratory physics over into the equally firm, but unexplored region of 

 mathematical cosmical physics. 



* One hundred and ninety miles were recorded on March 14, 1910. 



