SURVPJY OF THE BRITISH ISLES FOR THE EPOCH JAHUART 1, I89L 527 
Table XIT. 
1 
No. of district. 
Dip in I88G at 
Central station 
used in 1886. 
Dip in 1886 at 
Central station' 
used in 1891. 
Dip in 1891 at 
Central station 
used in 1891. 
Secular change 
1886-0 to 1891-0. 
I. 
71 Ao 
71 Ao 
70-57-3 
— tA 
II. 
70 19-6 
70 15-5 
70 9-3 
-6-2 
III. 
69 30 
68 59-2 
68 53'6 
-5'6 
IV. 
67 45-6 
67 49T 
67 42-2 
-6-9 
V. 
69 59 8 
70 0'3 
69 52'6 
-7-7 
1 
VI. 
69 •24-8 
69 26-1 
69 19-5 
-6-6 
VII. 
67 41-2 
67 39'1 
67 32T 
-7-0 
VIII. 
69 24-3 
69 20-8 
69 11-9 
-8-9 
IX. 
68 18-2 
68 11'6 
68 5-2 
-6-4 
(2.) Secular Change from Repeat Stations. 
As all the central stations lie at some distance from the coast, it was desirable that 
the evidence deduced from them should be reinforced bj observations taken near the 
borders of the area we were studying’. 
In 1892, therefore, observations were made at 26 stations, which had been included 
in the earlier survey. These were not scattered uniformly all over the country, but 
were divided into small groups near the coast. The mean value of tlie secular 
changes observed at each group of stations was assigned to the position defined by 
the mean of their latitudes and longitudes. 
In the following table the groups are lettered from A to G. The secular change is 
taken not from the observations reduced to January 1, 1886 and 1891 respectively, 
but over the whole interval which elapsed between the two sets of observations at 
the same station. The requisite data are given in the detailed accounts of tlie 
observations at the several stations in this paper and in the “ 1890 Memoir.” 
From these the secular change for five years is calculated on the hypothesis that 
it has been constant during the interval in question. 
