274 
Abstracts of the Makeestoun 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, . . 0 848. 
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 
0-055, and that for the mean meteorological seasons being 0-044. The range of the monthly means is 0-104. 
Extrem.es of the Daily Means, and the Ranges for each Month. 
Jan. Feb. March. April. May. June. July. Aug. Sept. Oct. Nov. Dec. 
Greatest, 0-935 0-985 0-929 0-913 0-991 0-973 0-935 0-952 0-956 0-978 0-992 0-965 
Least, 0-687 0-749 0-757 0-698 0-726 0-676 0-709 0-759 0-654 0-763 0-769 0-759 
Range, 0-248 0-236 0-172 0-215 0-265 0-297 0-226 0-193 0-302 0-215 0-223 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, beine 
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 
0 
12 
0-833 
0 
11 
0-852 
14 
11 
0-884 
16 
11 
•854 
1 
10 
•844 
1 
12 
•829 
15 
12 
•S42 
17 
10 
•873 
2 
11 
•847 
2 
9 
•863 
16 
9 
•S19 
18 
11 
•870 
3 
9 
•841 
3 
11 
•839 
17 
11 
•817 
19 
10 
•858 
4 
11 
•846 
4 
12 
•848 
18 
12 
•S44 
20 
9 
•853 
5 
10 
•848 
5 
11 
•835 
19 
11 
•816 
21 
12 
•849 
6 
9 
•830 
6 
12 
•857 
20 
12 
•S74 
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 
•S72 
25 
11 
•851 
10 
9 
•853 
10 
11 
•S10 
24 
11 
■S79 
26 
10 
•862 
11 
11 
■852 
11 
12 
•S61 
25 
12 
•863 
27 
9 
•829 
12 
10 
•819 
12 
11 
■S60 
26 
11 
•S49 
28 
11 
•899 
13 
9 
•823 
13 
12 
•S61 
27 
11 
•S37 
29 
9 
•862 
14 
12 
•831 
This Table has been formed from Table XII. in the manner already referred to, Table X. 
