120 SMITHSONIAN iMlSCIiLLANEOUS COLLECTIONS VOL. 79 



ST. HELENA 



Lat. 15° 57' S. Long. 5° 40' W. 

 Pressure. 



Authorities: 1892 to 1920. Manuscript returns compiled by- 

 Henry S. Hands, Esq., until 1898 February and by A. L. C. 

 Hands, Esq., since that date, and filed in the Meteorological 

 Office, London. 



Changes of Site: Some uncertainty exists about the actual height 

 of the barometer at St. Helena. A change of site occurred on 

 November 20, 191 o, and the difference of elevation between 

 the old and new sites, as determined by survey, is 75 ft. 

 Height of cistern above Mean Sea Level was stated in 1892 

 to be 1905 ft., making the present height 1980 ft. A re-survey 

 by Capt. Mainwaring gave the present height as 1900 ft., but 

 a comparison with some earlier observations at a low-level 

 station and with isobaric charts of the South Atlantic sug- 

 gests that this determination is about 100 ft. too low. An 

 allowance has been made for the change in height of 75 ft., 

 by applying the following corrections to the values from 

 1892 to 1910, November 20: 



Instrument: Barometer no. A. 202 by Adie, with an index error 



correction of —.014 in. was in use throughout the period. 

 Hours: The hour of observation was 9*^, local time, throughout 



the period. 

 Notes: All values have been corrected to normal gravity (Lat. 



45°) by applying a correction of —.061 in. 

 Mean Temperature. 



Authorities: As for Pressure. 



Site: The height of the thermometer screen above Mean Sea 



Level is about 1900 ft. There has been no change of site 



during the ])eriod of observations. 

 Hours: The hour of observation was cj\ local time, throughout 



the period. 



PrECTI'ITATION. 



Authorities: As for Pressure. 



Site: The site of the rain gage was changed on November 20, 

 1910. Previous to that date the height was given as 1890 ft., 

 and subsequently as 2020 ft., but for the reasons given under 

 " Pressure " these heights are only approximate. 



