SURVEY OF THE BRITISH ISLES FOR THE EPOCH JANUARY I, 1886. 301 
accuracy of our results obtained on three different occasions and at two stations, and 
we can only suppose either that there has been a real change or that Mr. Welsh’s 
station was subject to some very great local disturbance. Lochgoilhead, which our 
observations place just over the valley line in the next district is, according to W^ei.sh, 
just within this. At Pitlochne there is a large angle between the two forces. It is 
doubtful whether the valley line is here correctly drawn. The region of high Merticel 
Higliland. Di.strict. 
Force near Crieff seems to belong to the next district. At Crieff itself the disturbance 
of the Vertical Force is a maximum, and there is probably a peak in the neighbour¬ 
hood. The direction of the Horizontal Force cannot therefore be deduced from the 
Vertical Forces, and the fact that it happens to act northwards has perhaps led to its 
being wrongly included in this district. If the valley line runs direct from Alford to 
Lochgoilhead it would pass close to Pitlochrie. Our result would thus make its 
