246 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 5 1 



§37. Influence of simultaneous systems of wind 



In nature we generally find that various systems of wind exist 

 simultaneously. The simultaneity of two or of many barometric 

 maxima or minima produces certain disturbances in the systems 

 of isobars of each system of wind' and especially do the isobars de- 

 viate from the normal form along the passage from one system to 

 another. 



We shall illustrate the passage of the wind from one system to 

 another by an example which offers an analogy with certain cases 

 of nature. Consider a horizontal motion and assume that the vel- 

 ocities along the axes X, O Y and Z assume the form 



u = M y, v = M x, and w = ■]) 



Substituting these values in equations (i) and (2) of §35, we have 



1 dp 



- ■ -,- = - 2 co sin 6 ' M x - k M y - M 2 x (2) 



p dx 



1 dp 



- • -3- = 2 co sin 6 • M y - k M x - M 2 y (3) 



p dy 



By integration we shall find 



P ~ Po 



— — = -i x 2 (2 co sin 6 ' M +M 2 ) - 



- k M xy + hf (2 w sin . M - M 2 ) 



and by introducing 



2 co sin 6 



tang a = 



K 



we shall have 



kM\ , / M\ n .,/' M\ 



■■—j— y I tang o; — — I — 2 xy — x-\ tang a + 1 

 2 \ k I \ k 1 



(4) 



M 



If tan a > — , then the isobars represented by equation (4) are 



hyperbolas. 



