WHOLE VOL. NOTES. SOUTH AMERICA 67 



PUNTA TORTUGA 

 Authority. 



Servico Meteorologico Territorio Maritimo, 1901-1910; Institute 

 Central Meteorologica y Geofisco de Chile, 191 1- 

 1924; Oficina Meteorologica de Chile, 1928-1930. 

 Pressure. 



The hours of observation were as follows : 



1901 January-1906 July 8 h , I4 h , 2i h 



1906 August-1910 December j± h , io h , 16 11 



191 1 January-1928 December j h , 14 11 , 21 11 



1929 January-1930 March 7 h , 13", 2i h 



1930 April-1930 December 7 11 , 13 11 , i8 h 



Correction to reduce these different combinations of hours 



to mean of day were obtained from the 5 years' 

 hourly values at Santiago (1911-1915) as follows: 



Pressure Corrections to -?.£ Hours in Tenths of Millimeters 



Hours Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. 



4(8 +14 + 21) -2 -2 -2 -1 -1 -1 -1 -1 -1 -1 -2 -2 



£(7| + 10+16) -1 -1 -1 -1 -1 -2 -2 -2 -1-1 



4(7 +14+21) -2-2-1 0-1 -1 -2 -2 



J(7 +13 + 21) -3 -3-2-1 -1 -1 -2 -2 -3 



4(7 +13 + 18) 0+1+1+1+1 0+1 



The height of the barometer above Mean Sea Level was 27 m 

 until December 31, 1928, when it was lowered 

 2 m. The data given refer to the former height. 

 Temperature. 



The mean temperature from January 191 1 to December 1928 is 

 the mean of the usual hours of observation, the 

 formulas being |(7 h +i4 h + 2i h + 2i h ). For the 

 years 1901, 1906 to 1910, and 1929 and 1930 the 

 mean of the Max. and Min. was taken, the values 

 being corrected to the above combination of hours 

 by a comparison between the two sets of values 

 extending over the 10 years 1919-1928, as follows: 

 Correction to reduce the mean of |(Max. + Min.) to 

 J(7 h +i4 h + 2i h + 2i h ) : 



Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. 

 °C. -0.4 -0.4 -0.4 -0.2 -0.1 -0.2 -0.2 -0.2 -0.1 -0.2 -0.2 -0.3 



Until 1905 the Punta Tortuga values were not satisfactory, 

 the minimum thermometer being clearly out of 

 order until August 1903, so that the hourly mean 

 temperatures of La Serena were used to fill the 



