262 RESULTS OF THE METEOROLOGICAL OBSERVATIONS TAKEN DURING 



Pressure exceeds the mean of the whole day from 7 a.m. to 8 p.m., and is below it 

 from 9 P.M. to 6 a.m., the maxima, sj^eaking broadly, being during those hours when the 

 temperature is above the average for the day, and the minima when the temperature is 

 under the normal for the day. 



Cloudy Weather. 



It will be seen that the barometric curve for cloudy days in Spring and Autumn 

 exhibits an evening maximum and a morning minimum, pressure being above the mean 

 from about 7 p.m. to 4 a.m. and below the mean from 5 a.m. to 6 p.m., being essentially 

 the reverse of what obtains in clear weather at these seasons. The Summer and Winter 

 curves, however, differ in a striking degree. In Summer we have the principal minimum 

 at 3 a.m., and a secondary at 9 and 10 a.m., while the primary maximum is at 7 and 

 8 p.m. In Winter the curve is irregular, the primary maximum being at 10 a.m., after 

 which pressure falls to the minimum for the day at 5 p.m. A slight increase then takes 

 place till 8 p.m., after which j^ressure falls to a secondary minimum at 11 p.m. The 

 following are the hours of maxima and minima : — 



