5G 



TEMPERATURE. 



amplitudes. For this purpose tlie nb.servatious made during tlic southern march of the Polar 

 Party have been plotted in figures ■i'Ja and 22b. The lesults of this party have been chosen, 



because, as already stated (page 19), the 

 observations made with sling thermometers 

 are wtll spaced over the day, and as mini- 

 mum thermometers were not used there can 

 be no question as to the reality of the low' 

 night temperatures. 



The temperature at Cape Evans is shown 

 in figure 22 by a thick line, and that of 

 th? BaiTiar by a thin line. On the latter 

 curve the observations of the two observers 

 (see page 20) are indicated by the use of 

 dots and circles. As the observers were 

 often separated by ten or more miles, and 

 as the temperature changes were so rapid 

 it is not surprising that on some occasions 

 the observations vary by a few degrees, but 

 whenever the temperature became fairly 

 constant it will be found that the observa- 

 tions agree very well. 



Between the 17th and 22nd November 

 there was onl}' a slight south-westerly breeze 

 on the Barrier and from the figure it will 

 be seen that the daily variation of temper- 

 ature during this period was enormous, the 

 average amplitude being 20°F. For com- 

 parison it may be stated that the mean daily amplitude over India is 19'2°F., while it is 

 only in the desert areas when the sun is nearly in the zenith at midday that the 

 amplitude goes above .39°F. Thus the Barrier with its relatively small change in daily 

 insolation, the sun only oscillating between 10° and 35° above the horizon, has occasionally 

 a temperature amplitude comparable with that of tropical India. 



Fig. 21. Daily variation of temperature. Harrier. 



Fig. 2'2a. Simultaneous temperature on Barrier and at Cape Evans. 



A comparison of the curves for the Barrier and Cape Evans reveals a most important 

 relationship : the maximum temperatures on the Barrier are only a few degrees below the 



