Observatio?is made at St. Petersburg, in 1830. 261 



must subtract 0°* 11 from the mean results found above, in or- 

 der to have the mean temperature of the year. We shall then 

 have 



The mean temperature of the year 1830... + 2 0, 98 Reaum. 



Or 38°'705 Fahr. 



I need not remind the reader, that the table given by Dr. 

 Brewster is probably applicable only to Scotland and to si- 

 milar climates. I have employed it here because we do not yet 

 possess for St. Petersburg meteorological observations exe- 

 cuted upon the model of those which have been made with so 

 much perseverance at Leith, under the care of Dr. Brewster. 



Table II. Extreme Variations of the Octogesimal Thermometer 

 for every Month of 1830, and the Maximum of the Difference 

 for each Months between two Observations of the same Day, 



This table does not give the greatest variations of tempera- 

 ture in the course of a month, or during 24 hours. We must 

 admit that the maxima of temperature take place at 2 h p.m. 

 But for the minima we know that they occur a few instants 

 after sunrise; so that at 7 h a.m. the temperature during the 

 greatest part of the year is considerably above the minimum. 



Table III. Mean of Barometrical Observations made at 7 h a.m., 

 2 h p.m., and 9 h p.m., for every Month of the Year 1830. 





Mean barometric height for 1830...... 28*1 16 inches. 



