Relative Humidity. 
273 
The periods of maxima for the four meteorological seasons are as follow : — 
Spring, l h 10 m p.m. Makerstoim mean time. 
Summer, l h 0 m p.m. 
Autumn, 0 h 45 m p.m. 
Winter, l h 30 m p.m. 
The Year, l h 0 m p.m. 
A secondary minimum occurs in Summer at 3 h 40 m p.m., and a secondary maximum about 5 h p.m. There 
is a marked inflection in the curve for Autumn at 3 h 10 m p.m. In the mean for the whole year, the secondary 
minimum probably occurs about 4 h p.m., the secondary maximum about 5 h p.m. 
The periods of maxima and minima for the four astronomical seasons are — 
Spring, principal max., l h 40 m p.m. 
Summer, l h 20 m p.m. Secondary min., 4 h 10 m p.m. Secondary max., 5 h 0 m p.m. 
Autumn, 0 h 0 m Noon. 3 h 40 m p.m. 5 h 10 m p.m. 
Winter, l h 10 m p.m. 
The mean pressure of aqueous vapour for the year occurs at 8 h 10 m a.m. 
8 h 10 m p.m. 
The interval between the periods is, . . . 12 h 0 m . 
Range of the Diurnal Variation of the Pressure of Aqueous Vapour. — The range is inexact for the sum- 
mer months; it is here, however, as evident, as in the previous cases of temperature, that the range is less in 
the summer months than in the months immediately preceding and succeeding. The greatest range is that for 
September, being about 0-100 inch. 
TABLE XII.— Mean Relative Humidity for each Civil Day, Week, and Month of 1843, 
Saturation being = 1. 
I Civil 
Day. 
Jan. 
Feb. 
March. 
April. 
May. 
June. 
July. 
Aug. 
Sept. 
Oct. 
Nov. 
Dec. 
1 
[ ] 
0-819 
0-835 
0-880 
0-772 
0-973 
0-792 
0-884 
0-893 
[0-825] 
0-946 
0-965 
2 
0-766 
•803 
•819 
[ -854] 
•850 
•944 
[ -779] 
•861 
•874 
■763 
•971 
•937 
3 
•914 
•922 
•769 
•795 
•829 
•883 
•775 
•847 
[ -821] 
•842 
•987 
[ -890] 
4 
•749 
•801 
•844 
•891 
•753 
[ -891] 
•709 
•867 
•714 
•848 
•860 
•889 
5 
•718 
[ -884] 
[ -831] 
•827 
•726 
•872 
•935 
•759 
•790 
•821 
[ -882] 
•820 
6 
•894 
•868 
•881 
•851 
•765 
•875 
•815 
[ -851] 
•841 
•876 
•841 
•759 
7 
•843 
•923 
•827 
•845 
[ -786] 
•797 
•812 
•894 
•779 
•831 
•856 
•859 
8 
[ -847] 
•985 
•849 
•841 
•821 
•778 
•857 
•952 
•790 
[ -899] 
■776 
•798 
9 
•911 
•852 
•848 
[ -788] 
•822 
•811 
[ -814] 
•790 
•804 
•911 
-849 
•956 
10 
•859 
•798 
•929 
•698 
•831 
•745 
•770 
•802 
[ -857] 
•975 
•992 
[ -883] 
11 
•857 
•753 
•918 
•716 
•784 
[ -827] 
•742 
•854 
•956 
•978 
•927 
•896 
12 
•928 
[ -828] 
[ -861] 
•776 
•807 
•848 
•887 
•880 
•946 
•774 
[ -920] 
•906 
13 
•935 
•869 
•792 
•733 
•877 
•920 
•864 
[ -870] 
•867 
•784 
•931 
•884 
14 
•796 
•854 
•831 
•754 
[ -852] 
•859 
•814 
•812 
•881 
•807 
•895 
•836 
15 
[ -883] 
•845 
•847 
•801 
•893 
•733 
•758 
•939 
•878 
[ -828] 
•929 
•823 
16 
•814 
•877 
•896 
[ -765] 
•939 
•697 
[ -835] 
•935 
•865 
•819 
•902 
•828 
17 
•898 
•917 
•896 
•768 
•814 
•818 
•879 
•926 
[ -877] 
•912 
• 881 
[ -864] 
18 
•930 
•870 
•887 
■778 
•786 
[ -764] 
•844 
•839 
•895 
•874 
•900 
■931 
19 
•930 
[ -893] 
[ -881] 
•758 
•731 
■863 
•854 
•804 
•859 
•831 
[ -898] 
•878 
20 
•915 
■749 
•892 
•802 
•772 
■731 
•864 
[ -842] 
•883 
■872 
•918 
•887 
21 
•888 
•969 
•896 
•779 
[ -865] 
•744 
•769 
•787 
■798 
•839 
•951 
•952 
22 
[ -894] 
•979 
•817 
•913 
•974 
•676 
•892 
•890 
•860 
[ -844] 
•839 
•856 
23 
•900 
•970 
•881 
[ -801] 
•991 
•768 
[ -825] 
•808 
•856 
•787 
•978 
•871 
24 
•873 
•933 
•922 
•739 
•939 
•791 
•710 
• 809 
[ -791] 
•872 
•964 
[ -899] 
25 
•861 
•907 
•814 
•784 
•935 
[ -755] 
•826 
•811 
•822 
•863 
•974 
•904 
26 
•827 
[ -890] 
[ -845] 
•787 
•913 
•797 
•889 
•907 
•654 
•840 
[ -897] 
•891 
27 
•881 
•826 
•875 
•753 
•872 
•785 
•756 
[ -834] 
•757 
•845 
•864 
•921 
28 
•687 
•867 
•757 
•877 
[ -891] 
•715 
•875 
■910 
•764 
•923 
■831 
•909 
29 
[ -798] 
•822 
•864 
•834 
•729 
•838 
•763 
•856 
[ -904] 
•769 
•845 
30 
•687 
•875 
[ -824] 
•822 
•732 
[ -833] 
•806 
•880 
•930 
•973 
•832 
31 
•885 
•854 
•972 
•782 
•812 
•938 
[ -886] 
Mean 
0-852 
0-873 
0-855 
0-800 
0-845 
0-803 
0-820 
0-850 
0-837 
0-860 
0-904 
0-878 
mag. and met. obs. 1843. 
