134 



THE ANDES OF SOUTHERN PERU 



doubtless by convectional rising, causes ascent of the compara- 

 tively humid air and the formation of cloud. Farther eastward, 

 as the topographic influence is more strongly felt, the cloudiness 



1894 1895 



Fig. 85 — Temperature curves for Mollendo (solid lines) and La Joya (broken 

 lines) April, 1894, to December, 1895, drawn from data in Peruvian Meteorology, 1892- 

 1895, Annals of the Astronomical Observatory of Harvard College, Vol. 49, Pt. '2, 

 Cambridge, Mass., 1908. The approximation of the two curves of maximum tempera- 

 ture during the winter months contrasts with the well-maintained difference in minimum 

 temperatures throughout the year. 



increases until on the border zone, about 8,000 feet in elevation, it 

 may thicken to actual rain. Data have been selected to demon- 

 strate this eastern gradation of meteorological phenomena. 



1892 1893 1894 1895 „.. 



10 



A 



m|j 



J 



A 



s 







N 



Ll 



j 



F 



M 



A 



M 



J 



J 



A 



s 



V 



N 







J 



[•• 



u 



A 



M 



J 



J 



A 



s 



o 



N 



[) 



J 



F 



M 



A 



M 



J 



i 



A 



s 







N 



D 





1 

























































































wi>. 



TER 



SUMME1 





w 



It 



ITEE 





3L 



MM 



ER 





W 



N 



TI 



:r 



SI 



M 



MEE 





w 



Ih 



T 



3R 































































A 













































Is 





\ 























A 





















1 



V 



"> 







































F 







A 



















-* 



y 





















/ 









\ 

















f 





— 



.^ 



"A 











,/ 











V 















1 























1 



> 











^Moll 



d( 



) 















\ 





1 







/ 













A 













1 























/ 













V, 









/ 













\) 



* 





/ 

























/ 























/ 



















s 









/ 













V 





/ 



















\ 







r 



J 























1 





















\ 



s- 







































V 



<, 



v 



/ 





































L 



1. 



oj 



1 

































































/ 







k ^ 



--. 





















. 





















S 



x 



"^ 



'•" 



s-' 



** 





'- 





















- 



- 





_ / 

















— 







-- 



■ s 



' 







s 







f. 















Fig. 86 — Mean monthly cloudiness for Mollendo (solid line) and La Joya (broken 

 line) from April, 1892, to December, 1895. Mollendo, 80 feet elevation, has the maximum 

 winter cloudiness characteristic of the seaward slope of the Coast Range (compare 

 Fig. 82) while the desert station of La Joya, 4,140 feet elevation, has typical summer 

 cloudiness (compare Fig. 83). Figures are drawn from data in Peruvian Meteorology, 

 1892-1895, Annals of the Astronomical Observatory of Harvard College, Vol. 49, Pt. 2, 

 Cambridge, Mass., 1908. 



At La Joya, a station on the desert northeast of Mollendo at 

 an elevation of 4,140 feet, cloudiness is always slight, but it in- 

 creases markedly during the summer. Caraveli, at an altitude of 



