26 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 90 



The later values have been reduced to a height of 53 ft. by 

 applying a correction of +.039 in. to +.042 in. 

 according to temperature. 

 Instrument: Kew Pattern barometer M.O. 1242 was in use 

 throughout, index error correction —.002 applied. 

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

 45°) by a PPlyi n g a correction of —.024 in. 

 Precipitation. 



Site: The height above Mean Sea Level of the ground on which 

 the rain gage stands was : 



1921-1929, May 29 46 ft. 



1929, May 30-1930 102 ft. 



The rim of the rain gage was 2 ft. above the ground at both 

 stations. 



GREENWICH METEOROLOGICAL AND MAGNETIC 

 OBSERVATORY 



Authority. 



Meteorological Office, Air Ministry, London, England. 



Site. 



The Meteorological and Magnetic Observatory is situated in 

 Greenwich Park, about \ mile (0.8 km) south of the Thames, 

 on an elevated piece of ground sloping steeply to the north 

 and west and less steeply to the east and commanding ex- 

 tensive views of London, the Thames Valley, and the plain 

 of Essex. 



Pressure. 



Pressure means refer to a height of 48.5 m above Mean Sea Level. 

 All means have been reduced at 32 ° F. but the correction 

 for gravity by reduction to Lat. 45 has not been applied. 



Temperature. 



The monthly means are taken from the " Greenwich Magnetic 

 and Meteorological Observations ", Annual Volumes. The 

 thermometers are placed upon a revolving stand in an open 

 position in the Magnetic Pavilion enclosure about 320 m 

 (350 yards) to the east of the Magnetic and Meteorological 

 Observatory. 



Precipitation. 



The rainfall is measured daily at 9 11 , 15 11 , and 2i h Greenwich Mean 

 Time in an 8-in. gage whose surface is 5 in. (12.7 cm) 

 above ground. The continuous record of Osier's self-register- 

 ing rain gage shows whether the amounts at 9 11 are to be 



