Pressure op Aqueous Vapour. 



271 



TABLE X. — Pressure of Aqueous Vapour, considered in relation to the Moon's Age and Declination, 



Moon's 

 Age. 



No. of - 

 Means. " 



i^Iean 



Bssure. 



Moon's 

 Age. 



No. of 

 Daily 



Means. 



Mean 

 Pressure. 



After 



Moon 



farthest 



North. 



No. of 

 Daily 

 Means. 



Mean 

 Pressure. 



After 



Moon 



farthest 



North. 



No. of 

 Daily 

 Means. 



Mean 

 Pressure. 



Day. 



15 



9 



in. 



299 



Day. 







12 



in. 



0-278 



Day. 

 6 



11 



in. 



0-257 



Dav. 



14 



11 



in. 



0-293 



16 



11 



290 



1 



10 



•284 



1 



12 



•255 



15 



12 



-285 



17 



10 



292 



2 



11 



•274 



2 



9 



•322 



16 



9 



-333 



18 



11 



311 



3 



9 



• 253 



3 



11 



-276 



17 



11 



-309 



19 



10 



279 



4 



11 



•280 



4 



12 



-271 



18 



12 



-298 



20 



9 



315 



5 



10 



•277 



5 



11 



-273 



19 



11 



-282 



21 



12 



298 



6 



9 



■305 



6 



12 



•259 



20 



12 



-288 



22 



9 



324 



7 



12 



•295 



7 



11 



-272 



21 



11 



-262 



23 



11 



295 



8 



10 



■310 



8 



12 



-267 



22 



12 



•305 



24 



10 



284 



9 



11 



•277 



9 



9 



-321 



23 



9 



-341 



25 



11 



285 



10 



9 



•281 



10 



11 



-292 



24 



11 



-317 



26 



10 



278 



11 



11 



•284 



11 



12 



•303 



25 



12 



-302 



27 



9 



297 



12 



10 



-293 



12 



11 



-302 



26 



11 



■278 



28 



11 



301 



13 



9 



-303 



13 



12 



-292 



27 



11 



-262 



29 



9 



303 



14 



12 



-285 















This Table has been formed from Table IX. in the manner already indicated, Table II. of the Abstracts 

 of the Magnetical Observations, excepting that no means for the Sundays were employed. 



Pressure of Aqueous Vapour with reference to the Moon^s Age. — From the above, and the following means 

 of groups, there seems to be a maximum of pressure about three days after the time of full moon, and a mini- 

 mum about three days after the time of new moon. 



12 days till 18 days, Full Moon, 



15 22 ... 



19 26 ... 



23 29 ... 



in. 



0-296 

 0-301 

 0-295 

 0-292 



27 days till 3 days, New Moon, 0-284 



7 ... 0-281 



4 11 ... 0-289 



8 14 ... 0-290 



Pressure of Aqueous Vapour with reference to the Moon^s Declination. — The means in the above Table 

 seem very irregular. The projected quantities shew four maximum peaks, which occur at intervals of seven 

 days, namely, on the 2d, 9th, 16th, and 23d days after the Moon has its greatest north declination ; but these 

 may be at once traced to the less number of observations from which the means are deduced for these days, 

 and this due to the want of means for the Sundays. The means of groups are as follow : — 



25 days till 3 days. Moon farthest North, 0-279 



6 ... 0-273 



4 10 ... 0-279 



7 13 ... 0-293 



11 days till 17 days, Moon farthest South, 



14 20 ... 



18 24 ... 



21 27 ... 



in. 



0-302 

 0-298 

 0-299 

 0-295 



Nov. 



Dec. 



in. 



0-311 



in. 



0-331 



These means shew the minimum about three days after the Moon has its greatest north declination, and 

 the maximum about three days after it has its greatest south declination. 



Extreme Daily Mean Pressures of Aqueous Vapour and the Ranges. 



Jan. Feb. March. April. May. June. July. Aug. Sept. Oct. 



in. in. in. in. in. in. in. in. in. in. 



Greatest, 0-342 0-259 0-304 0-322 0-359 0-365 0-489 0-541 0-529 0-417 



Least, 0-154 0-107 0-157 0-150 0-217 0-253 0-308 0-320 0-229 0167 0174 0191 



Range, 0-188 0-152 0-147 0-172 0-142 0-112 0-181 0-221 0-300 0-250 0137 0-140 



The greatest daily mean in the year is that for August 17, being . . 0*541 in. 



The least February 18, being . . 0-107... 



The greatest range of the daily means in any month is that for September, being 0-300 ... 



The least June, being 0-112... 



The i-ange of the daily means for the whole year 1843, is ... 0-434 ... 



