TEE POPULAR SCIENCE MONTHLY 



Crossing' one of the great salarcs in tlie province of Antofagasta. 



on tinder, particles of any ?ui)posed caliche are brought in contact with 

 a strip of biirninof cotton wiclcing. or media. If nitrate is present, the 

 particles ignite sharply, and Avith no further test an expert can tell ap- 

 proximately the percentage of nitrate present. 



The nitrate is so readily soluble that the deposits could not exist 

 even in a moderately rainy region, but there is little trouble on that 

 score in northern Chile. The high Andes on one side and the cold Hum- 

 boldt or Peruvian current on the other make Chile north of the 30th 

 parallel one of the driest regions in the world. Some places have 

 passed more than a decade without a drop of rain. Other places have a 

 few minutes of scattering sprinkles almost every year. This is said to 

 have been the case in parts of Antofagasta for many years prior to 1910, 

 when there was a heavy shower, followed in 1911 by two days of steady 

 downpour. These occurrences, with rain again in 191?. and, more 

 wonderful still, snow where people living in the region for a generation 

 never had seen snow, have led many residents to believe that " the cli- 

 mate is changing since Halley's comet went past." That water has 

 floAved here at times in the past is shown by the dry gullies and chan- 

 nels. Xumerous snow-fed rivers descend the western slopes of the 

 Andes, but their waters soon are evaporated or lost in the dry sands of 

 the pampa. For hundreds of miles along this coast not a perennial 

 stream enters the ocean. If absolute desert exists in the world, it lies in 

 the nitrate pampa. 



In crossing this region one can not help feeling the utter helplessness 

 of man in the face of such great expanses of waterless and lifeless 

 wastes. All directions lead to sand, more sand, even to the border of the 

 ocean itself. One fails at first to understand how men are willing to live 

 there year after year: why those who 2:0 away genorallv come back again 



