420 



Results of Makeestoun Obseevations, 1844. 



Annual Variation of Atmospheric Pressure. — In 1844, the monthly mean of the height of the barometer 

 was lowest in Februar)', being 29'321 in. ; and it was highest in May, being 29'980 in. : the range of the 

 monthly means, therefore, was 0'659 in. The following are the mean pressures, in inches, of mercury at 32° 

 for each of the meteorological quarters of 18-14 : — 



ID. 



Winter Dec, Jan., Feb., 29635 



Spring, March, April, May, 29-771 



Summer, June, July, Aug., 29'580 



Autumn, Sept., Oct., Nov., 29-592 



The mean pressure for the year 1844, = 29-645. 



The pressure of the atmosphere was least in summer, and greatest in spring. The three consecutive 

 months with the lowest mean pressure, are January, February, and March, the mean being 29-514 in. ; and 

 the three with the highest mean pressure are April, May, and June, the mean being =: 29-804 in. 



TABLE XIX. — Diurnal Range of the Barometer for each Civil Day, with the Weekly and Monthly 



Means, for 1844. 



Annual Variation of the Mean Diurnal Ranges of Atmospheric Pressure. — The mean of the diurnal ranges 

 is greatest for the month of March, bemg 0-298 in. ; and it is least for the month of May, being 0-124 in. The 

 annual variation of the diurnal ranges, is exactly the reverse of the annual variation of the pressures ; when 



I 



