Atmospheric Pressure. 



421 



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

 are as follow : — 



in. 



Winter, Dec, Jan., Feb., 0-217 



Spring, March, April, May, 0-202 



Summer, June, July, Aug., 0-162 



Autumn, Sept., Oct., Nov., 0-188 



ILL, 



The mean of the ranges for the year 1844, = 0-1 92. 



The range was greatest in winter, 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 Range of the Barometer, with reference to the Moon's Age and 



Declination, for 1844. 



Moon s tj 

 Age. R 



lean 



urnal 



ange. 



Moon's 

 Age. 



Mean 

 Diurnal 

 Range. 



After j 

 Moon -q 



farthest t> 



North. 



dean 

 urnal 

 ange. 



After j 

 Moon jj 

 farthest g 

 North. 



klean 

 urnal 

 ange. 



Day. 



15 



in. 

 219 



Day. 

 



in. 

 0-185 



Day. 

 



in. 



196 



Day. 

 14 



in. 



184 



16 



147 



1 



•246 



1 



220 



15 



184 



17 



142 



2 



•198 



2 



266 



16 



207 



18 



182 



3 



•185 



3 



211 



17 



152 



19 



260 



4 



•213 



4 



155 



18 



211 



20 



190 



5 



•221 



5 



229 



19 



175 



21 



202 



6 



•270 



6 



206 



20 



150 



22 



221 



7 



•190 



7 



190 



21 



171 



23 



243 



8 



•210 



8 



210 



22 



214 



24 



176 



9 



•206 



9 



168 



23 



175 



25 



151 



10 



•220 



10 



196 



24 



216 



26 



166 



11 



•146 



11 



180 



25 



258 



27 



256 



12 



•113 



12 



158 



26 



188 



28 



194 



13 



•116 



13 



134 



27 



221 



29 



219 



14 



•118 











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 diurnal 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 till 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 



5 o 



