.)_• SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 5I 



where b designates the mean barometric pressure, as soon as we 

 have determined the constant of integration by observation of the 

 barometer at only one point, for which also the force of gravity, 



uwy + /*ry + /*vy 



\\dx / V dy J \ dz / 



shall have been given. 



If the mean barometric pressures computed in this manner be 

 compared with the observed pressures, we get a sharp control over 

 the theory. 



It is only when in this way it shall have been shown that the 

 observed steady components of the motions of the atmosphere and 

 of the barometric pressures are not properly represented, that we 

 shall be justified in assuming that the friction of the particles of air 

 against each other and against the earth's surface exert a sensible 

 influence on the phenomena. In this case, and in so far as the 

 friction is assumed to be proportional to the square of the velocity 

 and uniform throughout the atmosphere, we shall have to replace 

 equation (A) by the following: 



Fd\ og9 -dv-dF-i* 1 (*yw*y +/ a? 



dx / \ dy I \ dz 



i*y + (*y + f»\\. 



dx/ \dy/ \dz I j 



By the introduction of the fourth term in the right-hand side of this 

 equation and of the undetermined constant, C, nothing of importance 

 is changed in the development above considered. 



