SURVEY OF THE BRITISH ISLES FOR THE EPOCH JANUARY I, 1886. 291 
The whole district may apparently be divided into four parts, of which the 
boundaries are indicated on the map by heavy lines. 
The southernmost is the region of the Reading disturbance. The tendency of the 
Horizontal Forces to act towards regions of high Vertical Force is unmistakeable. At 
King’s Sutton the direction of the resultant appears to be affected by the region 
of high Vertical Force to the north, near Kenilworth. At Worthing and Hyde the 
Horizontal Forces point direct to the Chichester peak. At Purfleet and Southend 
the directions of the Forces are more southerly than the distribution of the Vertical 
Forces would have led us to suspect. 
The most easterly district is that of the Wash disturbance. Near King’s Lynn 
the Vertical Force is great. It is greatest at Tilney, which is the central station. 
The Forces at neighbouring stations converge to a point to the north of this, and the 
Horizontal Force at Tilney itself is directed northward. It is therefore likely that 
here, as in the case of Reading, the true peak, though near, is not at the spot at which 
we found the greatest Vertical Force. It probably lies to the north of it. 
'fhe central district is that of the Leicestershire disturbance. Here the phenomena 
are more complicated, and we wish it to be distinctly understood that we think it 
probable that Melton Mowbray does not occupy the position of unique importance 
which our observations allot to it. Nevertheless, we must point out that the hypo¬ 
thesis that a narrow ridge of attracting matter runs somewhat in the position we have 
assigned to it, is remarkably supported by the direction of the Horizontal Forces at 
Coalville, Loughborough, Leicester, and Manton, which would all be explained on this 
hypothesis. At Melton Mowbray the directions are, of course, indeterminate by 
means of the Vertical Force, and it is quite possible that the phenomena observed 
there may be due to some relatively small dyke, and not to an uprising of a part of a 
widespread mass of igneous rock. Until this district is more fully surveyed we are 
justified in adopting the view represented on the map, which is consistent with all 
the known facts. 
There is, however, one station in the district, viz., Birmingham, which is not in 
harmony with the rest, as the direction of the Horizontal disturbing Force is toward 
the region of minimum Vertical Force. Perhaps this indicates that this region is not 
connected, as we have supposed, with the larger region of low Vertical Force to the 
west, but that the two are severed by a district of high Vertical Force running from 
Birmingham northward. Future investigation can alone decide this question. 
The most northerly of the four districts is almost outside the region of our special 
surveys. We only introduce it to show that there is a large region of high Vertical 
Force to the north of Melton Mowbray, and that, therefore, there is nothing anomalous 
in the northerly directions of the Horizontal Forces at Nottingham and Grantham. 
If it be true that in the Leicestershire disturbance the attracting matter lies within 
narrow limits, it is quite possible that at these stations the predominant influence may 
be that of the larger northern mass. 
2 P 2 
