288 



METEOROLOGY. 



Date. 



1857. 



January 22 



February 23 



March 23 



April 29 



May 22 i 



June 22 



July 22 



August 28 



September 23 ... 



October 21 



November 27 



December 23 . .. 



Sum . 

 Mean 



TIIERMOMETEB. 



Daily mean. 



48.00 

 54.00 

 52.00 

 62.66 



63. 66 

 70.66 

 77.00 

 66.33 



64. 00 

 59.00 

 52.66 

 43.33 



FTourly mean. 



48.50 

 53.75 

 50.38 

 61.88 

 62. 46 

 69.83 

 75.23 

 65.21 

 64.08 

 58.50 

 53.58 

 43.50 



Difference. 



+0.50 

 —0.25 

 —1.62 

 —0.78 

 —1.20 

 —0. 83 

 — 1.77 

 —1. 12 

 +0.08 

 —0.50 

 +0.92 

 +0. 17 



9.74 



0.81 



As this correction is deduced from the difference between the obser- 

 vations of a single isolated day in each month of the year, due caution 

 and allowance for variation of seasons and other disturbing causes 

 must be exercised. For this reason we have not applied the correction 

 to our tables, but purpose prosecuting the series of hourly observa- 

 tions ; and with a view to uniformity hereafter will adopt the term 

 days, commencing at 10 p. m.s mean time, Gottingen, on the Friday 

 preceding the last Saturdays of February, May, August, and Novem- 

 ber, and on the Wednesdays nearest the 21st of each of the other 

 months. Another and most important object in this connexion will 

 be the determination of the hours of mean temperature. As will be 

 seen in the table subjoined, the measures of the critical interval are so 

 from corresponding with the quantity obtained in all other localities, 

 and which are generally so near as to amount almost to a constant, 

 that the two times of the day at which the mean temperature occurs 

 can only be regarded as approximative. January aifords a solitary 

 instance of the daily mean temperature occurring after midnight, 

 viz: \1h. 30m. p. m. 



