XXI. ENGLAND. GREENWICH. Lett. 51 29' N. ; Long. 0'. 

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

 to obtain the true Mean Barometric Pressure for the respective Months. GLAISHER. 



English Inches. 



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



94 



I 



