Atmosphere and the Earth. 



251 



From which, 



Lastly, for the fourth meridian, from the observations of 

 Rockfort and Philadelphia, 



a = 86°, h = 75°.82. 

 And from which, 



The result calculated for Cumana deviates very much from 

 the observed ; but as Cumana also lies considerably to the east, 

 it is here like TenerifFe. The same is the case with Koniss- 



o 



berg, in the second meridian, whose terrestrial temperature is a 

 whole degree less by observation than calculation. Here a lo- 

 cal cause seems to lower the terrestrial as well as atmosphe- 

 ric temperature. In Konigsberg, the temperature of the air is 

 43°"25 : in Mittau, almost 2° farther north, and more to the 

 east, it is higher, viz. 44''.6, from very careful observations car- 

 ried on by Professor Pauker of Mittau for four years. The 

 observation of times, also, does not agree with the calculation. 



From these formulae we may easily find the terrestrial tem- 

 perature for every degree of latitude, under one of the meri- 

 dians for which the formulas are calculated. It is easily seen, 

 that we may readily find in these meridians the points in which 

 a temperature of 42''.25, 54P.5, or 65°.75 will be found. Lines 

 drawn through these points, arc the isogeothermal lines which 

 we have already noticed, and are represented in Plate IV. In 

 fact, if we eliminate the latitude I from the equation 



a — b siii^ Z= i? 

 wc (»blaiii, l>y the usual reductions, 



* Such a coiuciduucc of the observed and calculated resulU is only to be 

 a?cr)bcd to chance. 



