684 XCIX. 



England. — Greenwich. Lat. 51° 29' N. ; Long. 0° 0'. 



Corrections to be applied to the Means of the Hours of Observation, or Sets of Hours 



to obtain the true Mean Humidity for the respective Months. (Glaisher.) 



F 



The numbers wilhoul sign must be added ; those with the sign — must be subtracted. 



120 



