ADIABATIC CHANGES OF MOIST AIR NEUHOFF 



471 



temperature, that occurs at these altitudes. These adiabatic 

 tables give the values for the graphic presentations to which we 

 shall now turn our attention. 



§". 



THE GRAPHIC PRESENTATION 



It seems to be of importance to represent by curves the results 

 thus far obtained on account of the great advantage that the 

 graphic presentation of formulae has in meteorological studies, 

 since by the application of this method not only the connections 

 between temperature, pressure, and moisture in the atmosphere 

 are more easily perceived but also because laborious computations 

 may thus be avoided. 



We can express the relations between pressure and tempera- 

 ture for adiabatic changes of condition of moist air by a system 

 of coordinates whose horizontal axis presents the data as to 

 temperature and whose vertical axis presents those of pressure. 

 It is unimportant what units of length are used in these diagrams, 

 but in our case we use a square network in which the individual 

 sides of the squares represent i° C. and io mm of pressure, respec- 

 tively. In the present case the temperatures extend over a range 

 of from + 30 to — 30 and the pressures from 3oo mm to 76o mm . 

 If we consider air expanding adiabatically in the dry stage then 

 this condition is expressed by the equation (1) between the variables 

 p and t. 



If we compute the pressure for successive diminutions of tempera- 

 ture of 4 C. each and 

 enter the corresponding 

 values of p and t in the 

 coordinate network and 

 connect the individual 

 points by a continuous 

 curve which can be as- 

 sumed as running ap- 

 proximately in straight 

 lines between the plot- 

 -30° -zo" -10° 0° W° 2~u° 30°"' ted points, we then ob- 

 fig. 1. dry stage tain the adiabatic curve 



of the dry stage for the 

 initial condition 30 C. and 76o mm , which we will call the dry adi- 

 abat for 30 and 76o mm . 



In a similar way we compute for each io° the adiabats for 20 , 



700 

 760 



