jo smithsonian miscellaneous collections vol. 90 



Pressure. 



The pressure data from January 1921 to December 1927 are 

 from the observations made in the extreme SW. of the city, 

 and 15 m from the coast, while for the years 1928 to 1930 

 the Prado series of hourly values furnished by the Director 

 of the above institute were employed. Both sets are reduced 

 to sea level without gravity, so that to reduce to altitude 

 29.3 m and gravity a flat correction of —3.0 mm was em- 

 ployed, all the values being reduced to Mean Sea Level. No 

 correction is given to reduce the observations from 192 1 to 

 1927 to mean of 24 hours, since the means are derived from 

 readings taken at 7 11 , 14 11 , and 2i h plus the mean of the daily 

 extremes, a formula that does not lend itself to the applica- 

 tion of a flat monthly correction. 



Temperature. 



Until March 1925 the Port series of data \ ,(7 h + I4 h + 2i h + 

 Max. + Min.) were employed, the smoothed corrections to 

 reduce to the hourly series of the Prado 1911-1920 being 

 as follows : 



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

 °C. -0.1 -0.3 -0.G -0.7 -0.0 -0*4 -0.4 -0.4 -0.4 -0.3 



From April 1925 the Prado series were again employed. 

 Precipitation. 



Same as for temperature. A comparison of the two series for 

 the period 191 1 to 1920 gave the average annual rainfall at 

 the Prado 11 58 mm and at the Port 11 26 mm, so that the 

 two series are comparable. 



MONTEVIDEO 

 data given in volume 79, smithsonian misc. coll. 



Authority. 



Robert C. Mossman. 



The observations given on pages 1142-43 of volume 79, Smith- 

 sonian Misc. Coll., taken at the Observatory of the Prado, 

 have been supplemented by an earlier series referring to the 

 years 1 883-1 901 made at the Observatorio del Colegio Pio de 

 Villa Colon, situated 10 km north of the Prado and at a 

 height of 59.3 m above the sea, or rather above the Rio de la 

 Plata, which is the same thing. These observations appear 

 in a publication entitled " Normales para el Clima de Monte- 

 video," by Luis Morandi, Montevideo, 1900, which contains 



