INTERCHANGE OF HEAT VON BEZOLD 



411 



At present I will restrict myself to communicating the tauto- 

 chrones for Munich and for Nukuss. 



Singer has deduced ten day means 16 from the observations of 

 Prof. J. von Lamont at Munich extending over a period of 25 years, 

 and therefore'this series is especially appropriate for the determina- 

 tion of the dates on which the heat content of the ground is a maxi- 

 mum or a minimum and thence the determination of the annual 

 heat exchange. 



Unfortunately this series does not include observations at slight 

 depths, so that the values for the upper layer of 1.29 meters must be 

 extrapolated. T have performed this extrapolation graphically 



5 N 



_: <\j K — px rsi— — 





0° 



5° 10° 



FIG. 58 



15° 



20° 



but only in a rough way by the utilization of the observed tempera- 

 tures of the air; but since the temperatures of the highest strata are 

 subject to important disturbances, as will be shown from the obser- 

 vations at Nukuss, therefore it seemed unwise to expend much time 

 and labor in attaining a result that would eventually not have the 

 assurance of great accuracy. 



Hence also in order to enable one to at once recognize this 

 uncertainty in the diagram the extrapolated portions of the curves 

 have been drawn in dashes. 



Moreover, in fig. 58, the tautochrones have been drawn for inter- 

 vals of 20 days only, although in the memoir of Singer the data are 



16 Lang and Erk. Met. Beobachtungen im Konigreich Bayern im Jahr. 

 389. Anhang, p. 10. 



