THE HIGHEST METEOROLOGICAL STATION IN THE 



WORLD.* 



By A. Lawrence Rotch. 



By the will of Mr. Uriah A. Boydeii, a considerable sum of money was 

 left in 1887 to Harvard College Observatory to aid in the establishment 

 of an observatory " at such an elevation as to be free, so far as i^racti- 

 cable, from the impediments to accurate observation which occur in the 

 observatories now existing, owing to atmosi)heric influences." Pre- 

 liminary stations were accordingly established in Colorado and in Cali- 

 fornia, provided with meteorological and astronomical instruments to 

 test the meteorological as affecting the visual conditions. From these 

 observations it was concluded that the selection of a proper site was 

 Ijy no means a question of elevation alone, and it was thought desira- 

 ble, from theoretical considerations, to secure a location within the 

 tropics. 



An expedition was accordingly sent to South America, where a sta- 

 tion on Mount Harvard, near Lima, Peru, at an elevation of 0,000 feet, 

 Wiis occui)ied for a year, and other sites further south were examined 

 by the Messrs. Bailey. Owing to the remarkable clearness and steadi- 

 ness of the air at Arequipa, Peru, it was finally decided to locate a 

 l)ermanent station there, and, under the direction of Prof. W. II. Pick- 

 ering, land was purchased outside this city and the observatory build- 

 ings were erected in 1891. The city of Arequipa is situated above a 

 desert about 80 miles from the Pacific Ocean, in a little oasis formed 

 by a river valley at the foot of the Cordillera. The observatory is 

 built upon the crest of a hill overlooking this valley, about 400 feet 

 above the city and 8,050 feet above the sea. It stands approximately 

 in 1(P 22' S. latitude and in 71° 22' W. longitude. Eastward the 

 extinct volcano of Pichu-Pichu rises to a height of 18,000 feet; north- 

 east, and 10 miles distant, is the quiescent volcano of the Misti, 19,200 

 feet in altitude, and 12 mih^s north rises Charchani, 20,000 feet high, 

 which is always snow-capped. 



The meteorological station, forming the subject of the article, is situ- 

 ated on the latter mountain just below the permanent snow line. 



* Froiu American Meteorological Journal, October, 1893, vol. x, pp. 282-287. 



253 



