134 
The mean annual decrease in the dip of 1-81 minutes 
corresponds very well with that of 2'’02 as found from the 
Kew observations from 1857 to 1874 inclusive, and l'*90 
from the Stonyhurst observations from 1871 to 1874 inclusive. 
Table II. 
HOEIZONTAL FOECE. 
1873, 
1874. 
1875. 
1876. 
Mean of 
4 Years. 
January 
3-694 
3^699 
3-700 
3-6977 
February . . . 
3-691 
3-693 
3-704 
3-6960 
March 
3-693 
3-692 
3-709 
3-695 
3-6972 
April 
3-691 
3-703 
3-702 
3-6987 
May 
3-686 
3-705 
3-693 
3-701 
3-6962 
June 
3-684 
3-700 
3-697 
3-708 
3-6972 
3-6877 
3"6955 
3-6990 
3-7017 
3-6971 
1873. 
1874, 
1875. 
1876. 
Mean of 
4 Years. 
i 
July 
3-704 
3-696 
3 693 
3-699 
3-6980 
August 
3-704 
3-709 
3-696 
3-699 
3-7020 
September ... 
3-715 
3-691 
3-697 
3-705 
3-7020 
October 
3-661 
3-691 
3-696 
8-701 
3-6872 
November ... 

3-689 
3-697 
3-703 
3-6963 
December . . . 
3-686 
3-691 
3-707 
3-702 
3-6940 
3-6940 
3-6945 
3-6977 
3-7015 
3-6966 
3-6916 
3-6950 
3-6983 
3-7016 
3-6969 
1 
The values of the horizontal force, corresponding to the 
middle of each of the four years, and the annual increase for 
each year are as follows : — 
Annual 
Increase. 
Mean horizontal force for 1873 
>j }} 1874 
„ „ 1875 
« .. 1876 
1 
3-6916 
3-6950 
3-6983 
3-7016 
•0034 
-0033 
•0033 
_ 
3-6969 
•0033 
1 
