Atmospheric Peessuee. 



421 



the mean pressure increases, the range diminishes, and vice versa. The means for the meteorological quarters 



are as follow : — 



in. in. 



Winter Dec, Jan., Feb., 0'217 Summer, June, July, Aug., 0-162 



Spring, March, April, May, 0-202 Autumn, Sept., Oct., Nov., 0188 



in. 

 The mean of the ranges for the year 1844, = 0-192. 



The range was greatest in wiater, and least in summer. The three consecutive months with the greatest 

 mean of ranges are January, February, and March, the mean being 0-268 in. ; and the three with the least 

 mean of ranges are May, June, and July, the mean being 0-143 in. 



TABLE XX. — Diurnal Eange of the Barometer, with reference to the Moon's Age and 



Declination, for 1844. 



Table XX. has been formed from Table XIX. in the manner already described for Table II. of the mag- 

 netical results. 



Variation of the Diurnal Range of Atmospheric Pressure with the Moon's Age. — The following are means 

 of groups from the first portion of Table XX. : — 



12 days till 18 days, Full Moon, 0-148 



15 22 ... 0-195 



19 26 ... 0-201 



23 29 ... 0-201 



27 days till 3 days. New Moon, 0-212 



7 ... 0-213 



4 11 ... 0-209 



8 14 ... 0-161 



The dim-nal range of atmospheric pressure is least at full moon, and is greatest about new moon. The 

 difference is well marked. 



Variation of the Diurnal Range of Atmospheric Pressure with reference to the Moon's Declination. — The 

 means of groups from the second portion of Table XX. are as follow : — 



25 days tiU 3 days. Moon farthest North,. . . 0-223 



6 ... 0-212 



4 10 ... 0-193 



7 13 ... 0-177 



MAG. AND MET. OBS. 1844. 



11 days till 17 days. Moon farthest South,. . .0-171 



14 20 ... 0-180 



18 24 ... 0-187 



21 27 ... 0-206 



5o 



