130 



THE ANDES OF SOUTHERN PERU 



for Callao, Mollendo, Arica, and Iquique), but interest in the 

 phenomenon is far from being confined to the theoretical. Every- 

 where along the coast the virazon, as the sea-breeze is called in 

 contradistinction to the terral or land-breeze, enters deeply into 

 the affairs of human life. According to its strength it aids 

 or hinders shipping; sailing boats may enter port on it or it 



7 a.m. 



OCT. -MARCH 



N 



Fig. 80 — Wind roses for the summer and winter seasons of the years 1911-1913. 

 The diameter of the circle in each case shows the proportion of calm. Figures are 

 drawn from data in the Anuario Meteorologico de Chile, Publications No. 3, (1911), 

 6 (1912) and 13 (1913), Santiago, 1912, 1914, 1914. 



may be so violent, as, for example, it commonly is at Pisco, 

 that cargo cannot be loaded or unloaded during the afternoon. 

 On the nitrate pampa of northern Chile (20° to 25° S.) it not 

 infrequently breaks with a roar that heralds its coming an 

 hour in advance. In the Majes Valley (12° S.) it blows gustily 

 for a half -hour and about noon (often by eleven o'clock) it 

 settles down to an uncomfortable gale. For an hour or two 



