Magnetic Survey of the British Isles 
for epoch I®.*January 1915, 
by G,W, Walker, Esq.I F.R.S. 
HilKll-ANIi 
oteTURBINC FORCES 
Horizontal Diiturbanae »hiwn in magnitude and direction! 
by an arrolv drawn from tl^e obaopving tia^iona 
The Male li 1""" • 20')' .2k<r*CBUw \ 
The numbol’ at the baac of >ho arrow give* the vertical 
diBturbancel in unite of I’f * 10 Cauia . 
For dislurbince downwanlal 
FoP'dlBturbdnce upwards 1 
OllKJfKy 
INLANDS 
KILLY 
S«mrV*/r 
11 
