274 



Abstracts of the Makerstoun Observations, 1843. 



Table XII, has been formed in the following manner : — / being the elastic force of vapour, the air being 

 saturated at the mean temperature t (Table I.), and /" the elastic force of the vapour actually in the air (Table 

 IX.), then h, the relative humidity in the previous table, is obtained from the formula, 



The values of/ were obtained from the tables in the Introduction to the Greenwich Observations, 1842. 



Annual Variation of Humidity. — This has not the same period as the temperature of the air or the pres- 

 sure of aqueous vapour ; the minimum occurs in June, and the maximum in Winter ; in the beginning of the 

 year February is a maximum, and in the end of the year November is the maximum. The following are the 

 means for three different classes of seasons, viz. : — 



The mean meteorological seasons, for which June, July, and August, constitute summer. 



The meteorological seasons for the year 1843, for which July, August, September, constitute summer. 



The astronomical seasons, for which May, June, July, constitute summer. 



Seasons. Mean Meteorological. Meteorological for 1843. Astronomical. 



Spring, . . 0-833 0-816 0-843 



Summer, . . 0-824 0-836 0-823 



Autumn, . . 0-867 0-881 0-849 



Winter, . . 0-868 0-860 0-878 



The year 1843, . . 0848. 



For the year 1843, the most regular group is that of the astronomical seasons. The greatest range of 

 the means is that for the meteorological seasons of 1843, being 0-065 ; that for the astronomical group being 

 0-056, and that for the mean meteorological seasons being 0-044. The range of the monthly means is 0-104. 



Extremes of the Daily Means, and the Ranges for each Month. 



Greatest, 

 Least, 



Jan. 

 0-935 

 0-687 



Range, 0-248 



Feb. 

 0-985 

 0-749 

 0-236 



March. 

 0-929 

 0-757 

 0-172 



April. 

 0-913 

 0-698 

 0-215 



May. 

 0-991 

 0-726 

 0-265 



June. 

 0-973 

 0-676 

 0-297 



July. 

 0-935 

 0-709 

 0-226 



Aug. 

 0-952 

 0-759 

 0-193 



Sept. 

 0-956 

 0-654 

 0-302 



Oct. 

 0-978 

 0-763 

 0-215 



Nov. 

 0-992 

 0-769 

 0-223 



Dec. 

 0-965 

 0-759 

 0-206 



November 10th was the most humid day, and September 26th the least humid day in the year, the ratio 

 to saturation for the former being 0-992, and for the latter 0-654. The total range of the daily means for the 

 year 1843 is therefore 0-338. The greatest monthly range of the daily means is that for September, being 

 0-302, and least monthly range is that for March, being 0-172. 



TABLE XIII.— Relative Humidity, Saturation being = 1, with reference to the Moon's Age 



and Declination. 



Moon's 

 Age. 



No. of 

 daily 

 Means. 



Humidity. 



Moon's 

 Age. 



No. of 



daily 



Means. 



Humidity. 



After 



Moon 



farthest 



North. 



No. of 



daily 

 Means. 



Humidity. 



After 



Moon 



farthest 



North. 



No. of 



daily 



Means. 



Humidity. 



15 



9 



0-843 







12 



0^833 







11 



©•852 



14 



11 



0-884 



16 



11 



•854 



1 



10 



•844 



1 



12 



•829 



15 



12 



•842 



17 



10 



•873 



2 



11 



•847 



2 



9 



•863 



16 



9 



•819 



18 



11 



•870 



3 



9 



•841 



3 



11 



•839 



17 



11 



•817 



19 



10 



•858 



4 



11 



•846 



4 



12 



•848 



18 



12 



■844 



20 



9 



•853 



5 



10 



•848 



5 



11 



•835 



19 



11 



•816 



21 



12 



•849 



6 



9 



•830 



6 



12 



•857 



20 



12 



•874 



22 



9 



•855 



7 



12 



•850 



7 



11 



•856 



21 



11 



•877 



23 



11 



•880 



8 



10 



•872 



8 



12 



•831 



22 



12 



•849 



24 



10 



•862 



9 



11 



•860 



9 



9 



■826 



23 



9 



•872 



25 



11 



•851 



10 



9 



•853 



10 



11 



•810 



24 



11 



•879 



26 



10 



•862 



11 



11 



•852 



11 



12 



•861 



25 



12 



•863 



27 



9 



•829 



12 



10 



•819 



12 



11 



•860 



26 



11 



•849 



28 



11 



•899 



13 



9 



•823 



13 



12 



•861 



27 



11 



•837 



29 



9 



•862 



14 



12 



•831 















This Table has been formed from Table XII. in the manner already referred to. Table X. 



