METEOROLOGICAL RECORDS 179 



FREQUENCY OF DIURNAL VARIABILITY AT COCHABAMBA, 1906 



Degrees F. 



J. 



F. 



M. 



A. 



M. 



j. 



J. 



A. 



s. 



o. 



N. 



D. 



Total No, of 

 days 



o 



1 



3 



10 



12 



6 



10 



9 



6 



9 



6 



3 



4 



79 



0-1 



5 



— 



3 



5 



3 



3 



— 



4 



— 



3 



1 



1 



28 



1-2 



10 



10 



13 



11 



15 



7 



14 



11 



15 



10 



14 



13 



143 



2-3 



7 



11 



3 



1 



5 



8 



7 



4 



3 



6 



7 



6 



68 



3-4 



6 



2 



2 



1 



2 



2 



1 



6 



3 



4 



3 



5 



37 



4-5 





















1 



1 



1 



3 



Over 5 



2 



2 

















1 



1 



1 



7 



A series of curves shows the daily march of temperature at 

 various locations along the seventy-third meridian. Figs. 109 to 

 113 are for the Urubamba Valley. Eespectively they relate to 

 Pongo de Mainique, 1,200 feet elevation (365 m.), the gateway to 

 the eastern plains; Yavero, 1,600 feet (488 m.), where the tribu- 

 tary of this name enters the main stream; Santo Anato 1,900 feet 

 (580 m.) ; Sahuayaco, 2,400 feet (731 m.), and Santa Ana, 3,400 

 feet (1,036 m.), one of the outposts of civilization beyond the East- 

 ern Cordillera. The meteorological conditions shown are all on 

 the same order. They are typical of dry season weather on the 

 dry floor of a montana valley. The smooth curves of clear days 

 are marked by high mid-day temperatures and great diurnal 

 range. Santo Anato is a particularly good illustration : the range 

 for the 24 hours is 38° F. (21.1° C). This site, too, is remarkable 

 as one of the most unhealthful of the entire valley. The walls of 

 the valley here make a sharp turn and free ventilation of the 

 valley is obstructed. During the wet season tertian fever pre- 

 vails to a degree little known east of the Cordillera, though 

 notorious enough in the deep valleys of the plateau. The curves 

 show relative humidity falling to a very low minimum on clear 

 days. At Santo Anato and Santa Ana, for example, it drops 

 below 30 per cent during the heat of the day. Afternoon cloudi- 

 ness, however, is a common feature even of the dry season. 

 A typical afternoon cloud formation is shown in Fig. 114. The 

 effect on temperature is most marked. It is well shown in the 

 curve for August 20 and 22 at Yavero. Cloudiness and precipita- 



