Prof. Kupffer on the Mean Temperature oflrkoutsk, in Siberia. 3 



Table containing the Means of Ten consecutive Year, 



Observations on the preceding Results. 



(See this Journal, vol. i. pp. 135, 260, 428.) 



It appears from the last of these tables that the mean tem- 

 perature of Irkoutsk for ten years is + 0°*31of Reaumur, or 

 32°*7 of Fahrenheit, at the hours of 7 h a.m. 2 h p.m. and 9 h p.m. 

 Now it appears from the Leith hourly observations that the 

 mean temperatures of these hours differ from the mean tem- 

 perature of the day, in the following manner : 



7 h A.M -l°-983 Fahr. 



2 p.m + 3°'203 



9 P.M — 0°'43S 



-2 -421 



+ 3°'203 

 -2 -421 



+ -782 

 Hence the mean temperature obtained from the tables ex- 

 ceeds the true mean temperature of the twenty-four hours by 

 o, 782. The reason of this is obvious, from the circumstance 



B2 



