T923. No. 8. THE AURORAL SPECTRUM AND TIIF ATMOSPHERE. 



Table \' 



Recently a most interesting paper has been published by Lindem.\nn 

 and DoBsox,' dealing with the meteors. They have tried to calculate the 

 amount of gas which a meteor must traverse in order to obtain the tempe- 

 rature necessary for explaining its behaviour at the various heights. 



They come to the conclusion that the density at a height of, sav, 100 km. 

 must be considerabh- greater than that ordinarely found, and they conclude 

 that the higher strata must have a temperature of about 300 absolute. 



Now we can easily calculate the pressures at various heights when 

 we know the composition of the atmosphere 1 km. above the ground, 

 and suppose that above this height the temperature is 300 absolute. 



The pressure is found from a formula of the form : 



ih -ho) 



Ph = po c 



(1 



Let ho be 10 km. then po is the pressure at 10 km. If, now, we have 

 calculated the pressure for one temperature, we can easily find the pressure 

 distribution at another temperature in the following way : 



At the temperature T and a height h the pressure p will be equal 

 to that at a certain height //' at the pressure 7\ provided that: 



//' 



//,. 



T, 



(2) 



We have, in other words, by means of this formula to calculate the 

 heights //' which, for a temperature T^, corresponds to a height // and a 

 temperature T. 



' F. A. LiNDEMANx and G. :SI. B. Dobsox : A Theory of Meteors and the Density and 

 Temperature of the outer Atmosphere to which it leads. Proc. of Roy.il Soc. A. 102, 

 p. 411. 



