XXIII 



THE MECHANICAL EQUIVALENT OF ANY GIVEN DISTRI- 

 BUTION OF ATMOSPHERIC PRESSURE, AND [THE 

 MAINTENANCE OF A GIVEN DIFFERENCE IN PRES- 

 SURE 



BY MAX MARGULES 



[Read at the meeting of the Imperial Academy of Sciences, Vienna, July 

 ii, 190 1, commemorating the Jubilee of the k.k. Central Institute for Meteorol- 

 ogy and Terrestrial Magnetism; translated from the Jubilee volume] 



In this memoir some minor studies connected with the problem 

 of the cyclone have been collected together as a contribution to 

 this memorial volume of the Central Institute for Meteorology. 



In Part I there is determined the work that must be done in order 

 to transfer air from any prescribed condition of equilibrium over 

 to any other distribution of mass. In a closed atmospheric system 

 this work is to be considered as potential energy. The comparison 

 of the kinetic energy of a simple vortex with its potential energy 

 teaches that the kinetic is by far the greater. 



In Part II the discussion relates to the well-known scheme of 

 circulation for columns of air of unequal temperatures. The cal- 

 culation of the additional heat necessary for the maintenance of 

 any given horizontal difference of pressure and its useful effect — 

 or coefficient of efficiency — still remained to be accomplished as is 

 now done in this part. 



In the concluding Part III will be found a general calculation 

 as to the loss of energy in moving air. The internal friction can 

 have only an inappreciable influence on large systematic atmospheric 

 currents. Even the complex small movements that pervade 

 general atmospheric currents consume less of the kinetic energy of 

 the wind than the lowest stratum gives up in starting and main- 

 taining the waves of the ocean, or in concussion against the obstacles 

 offered by the solid ground. 



5°i 



