THE MECHANISM OF THE AURORA 



lies in the nullovalent elements of the atmosphere (p. 220). 

 The common gases constitute FOUR DISTINCT STRATA in 

 our atmosphere, of which the estimated thickness is here 

 given in myriameters (about six English miles each). See 

 my papers, Comptes Rendus, August 20, 1900, and National 

 Druggist, Sept. 1900. 



I. LOWER ATMOSPHERE, with aqueous vapor and car- 

 bon dioxide, 2 myr. 



II. OXYGEN STRATUM, 3 myr.; from 16 to 10 % O. 



III. NITROGEN STRATUM, 5 myr.; from 84 to 4 % N. 



IV. HYDROGEN STRATUM, 7 myr.; from 80 to 100 % H. 

 The NULLOVALENT GASES occur according to their 



densities: 



XENON and KRYPTON in the lowest stratum, I, exclusively. 



ARGON terminates in the oxygen stratum, II. 



NEON is most abundant in the upper half of the nitrogen 

 stratum, III; while 



HELIUM prevails in the lower part of the hydrogen 

 stratum, IV, reaching about 16 %. 



The main physical characters of these gases are: their 

 apparently high conducting power for heat and electricity, 

 together with the brilliant light they emit under high electric 

 tension ; this light is marked by characteristic spectra. 



The lower gases, Xenon and Krypton, thus must show 

 cloud-formations; the brightest green crypton line of 558 

 millimicrons is accordingly most characteristic of the lower 

 aurorae. 



All these gases will, by their greater electric conductivity, 

 form mobile threads dirigeable by the magnetic force of the 

 earth as do the iron filings on our glass plate above a 

 common magnet. 



From Krypton to Helium, thus beams may form several 

 myriameters in length, constituting great linear conductors 

 from the lower strata to the highest hydrogen stratum. 



These beams will show colored light, varying according 

 to the many varied conditions of pressure, per. cent amount, 

 intensity of discharge and kind of gas. 



This I consider an outline of the mechanism of the 

 Northern Lights. 



A paper on this subject was apparently lost in the mails 

 a year ago; hence this short note. 



