]2 Art. 1.— T. Terada: 



dp ^ _ }'U ^ f^ ^% 



dt ^ dx ~ (l dx' ' (^^ 



The aljove holds of course only for the highly idealized case con- 

 sidered; but, if the total amount of Uhe small and the variation 

 of w sufficiently rapid, the essential feature of the yariation of 

 pressure may roughl}^ be represented by (G), provided that the 

 stationary state expressed by (1) is established instantaneously. 



In the above calculation, the effect of the poriolis's force was 

 entirely put out of account. The comi^onent flow in y-direction 

 due to this influence will become considerable compared Avith ii, 

 especially for high latitudes and in high levels. Plowever, as long 

 as the assumption of parallel isobars and the uniform deviating 

 force is adhered, this component will bring no essential modifica- 

 tion to the form of the expression (G), except the value of the 

 constant factor. In applying the above theory to the actual 

 problems, however, the nature of the abstractions made in the 

 assumption must always be borne in mind. 



Again, in the above, we have tacitly neglected the influence 

 of the topography in affecting the thickness of the air layer subject- 

 ed to the daily yariation of temperature. In actual cases, ç will be 

 generally diminished with the elevation of the earth's surface, if 

 we provisionally assume that the temperature reduced to the sea- 

 level is everywhere uniform and the variation takes place as in the 

 case there were no elevation of land. In this case we must replace 



in the al)Ove equations l)y y . This makes ~~f. proportional 



to 



^■^„ , j^ ^ dd^ Jh ^ 

 dx' dx dx 



where A(.t) represent the elevation of the surface as a function of x. 

 Ivemembering the nature of the assumptions made at the c-ut- 

 set, let us simply take the form 



dp ^ ^ dti„ ^. ^ ^^^^,^^ • . ^,3,^ 



dt dx' ' ^ 



as at least (iiialitntively legitimate, neither entering upon the form 



