98 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 79 



Changes of Hours of Observation: 



1 87 1 July to 1 89 1 October. 9'', 15''. 



1895 September to 1904 November. 8'\ 



1904 December to 1920 June. 8'\ 15''. 



All values are corrected to the mean of 24 hours by correc- 

 tions (Table B) based on observations taken on 

 board H. M. S. " Carnarvon " at Nassau during 

 2 years. 

 Notes: All values are corrected to normal gravity (Lat. 45°), 

 by applying a correction of —.050 in. 



Tabi.f. a. — Corrections Applied for IJiffcrenccs of Height. Inches 



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

 44 ft. to 25 ft. +.020 in. througliout. 



47 ft. to 25 ft. +.023 in. throughout. 



12 ft. to 25 ft. — .013 in. throughout. 



Table B. — Corrections .ipplied for Reduction to Mean of 34 Hours. Inche.i 



Jan. Feb. 



J (9 + 1.5)" — .004 — .004 



8" — .005 — .005 



J(8 + 15)»' +.001 .000 



Mean Temperature. 



Authorities: As for Pressure, but the values previous to 1874, 

 January, were rejected as being doubtful. 



Site: See note under Pressure. 



Observations : The standard adopted is the mean of the mean 

 daily maximum and mean daily minimum. These 

 figures were unreliable or wanting in certain months 

 and the values in italics have been computed from 

 the fixed morning hour of observation by means 

 of the following correction obtained from a num- 

 ber of the most reliable records. 



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

 9'' °F. --0.5 — 0.9 — 1.5 — 1.9 — 2.0 — 1.9 — l.S —1.9 — 1.9 — 1.6 — 1.0 — 0.6 



8" "F. +0.4 +0.3 0.0 —0.3 —0.5 — 0.6 —0.7 —0.5 —0.4 — 0.3 —0.1 +0.1 



Precipitation. 



Auihoritics: As for Pressure. Data for 1866-1870 were ob- 

 tained from meteorological returns communicated 

 by the Royal Army Medical C'or])s and filed in the 

 Meteorological Office, London. 



Site: See note under Pressure. The values for the twtj periods 

 are probably comparable. 



