640 LXX. 



Tx-ussiA. — Helsingfors. Lat. 60° 10' N. Long. 24° 57' E. Greema. 



Corrections to be applied to the Means of the Hours of Observation to obtain the true 



Mean Temperatures of the respective Days, Months, and of the Year. — Dove. 



Degrees of Reaumur. 



The numbers without sign must be added ; those with the sign — must be subtracted. 



F 76 



