IX 



RESEARCHES RELATIVE TO THE INFLUENCE OF THE 

 DIURNAL ROTATION OF THE EARTH ON ATMOS- 

 PHERIC DISTURBANCES 



BY M. GORODENSRY 



Memoirs of the Imperial Academy of Sciences of Saint Petersburg, igo^, 



Volume XV, section g] 



[The original memoir above quoted is published in the Russian language' 

 the brief abstract, in French, communicated by the author to the " Annates" 

 of the Met. Soc. of France, Vol. LIII, pp. 1 13-120, May 1904, has been fol- 

 owed in the present translation] 



In order to study in detail the causes of the origin of atmospheric 

 disturbances and their more important properties it is first necessary 

 to resolve the fundamental problem : given a certain system of me- 

 chanical forces, how will it act on the air in the different strata of the 

 terrestrial atmosphere? We propose to seek the possible solution for 

 the special case of the strata situated in the immediate neighbor- 

 hood of the ground. 



It is easy to determine the action of any force in the midst of 

 an ideal gas, whose particles move among themselves without fric- 

 tion, as in a vacuum and according to the law of gravitation only. 

 In order to pass from such a gas to the atmosphere it is necessary 

 to know not only the special properties of the air itself but also 

 the value of the friction. The influence of this friction is appre- 

 ciable in two ways: (1) it diminishes the velocity of the progressive 

 movement of the air, (2) it enfeebles the action of the force per- 

 pendicular to this current of air, and to the same extent diminishes 

 the angular velocity of the atmospheric particles. The evaluation 

 of this normal friction, that is to say, the effect directed along the 

 line normal to the direction of motion is the subject that we propose 

 to study in this memoir. 



Fortunately there is at our disposition a very convenient agent 

 that one can utilize to this end. This is a well-known constant 

 force and one which is always perpendicular to the trajectory of 

 any mass that is moving on a horizontal plane: it is the action of 

 the diurnal rotation of the earth. 



i°5 



