4 45 
has been blowing, in the main, from east to west; but on arriving 
oF. at the brow above Langanby we should commonly find a gentle 
breeze blowing from the opposite direction, or from west eastwards 
_ —from the lowlands in the direction of the Escarpment. 
Phenomena of exactly the same nature prevail all along the zone 
_ traversed by the Helm Wind, whether the observation be made at 
Melmerby, at Kirkland, at Milburn, or at Knock. There is a 
long narrow zone of country along the fell sides where the violent 
easterly wind prevails, while parallel to that zone lies another 
where there is a small belt of calms, which again has on its lowland 
side a zone of gentle breezes travelling from the west to the east. 
More extended observations upon the direction of the Helm 
Wind shew that we are dealing with a cyclone, which is generated 
by some peculiar local causes, and which is clearly advancing in a 
spiral direction from the S.E. towards the N.W. along an axis 
situated a few hundred feet above the ground at the foot of the 
_ Escarpment. We have, in fact, phenomena analagous to a water- 
fall, only that instead of the visible fluid water, our cataract consists 
of the invisible fluid air. 
Everyone that has considered the subject has perceived that 
there must be an intimate connection between this phenomenon 
and the shape of the ground in the locality where the Helm Wind 
‘is generated. To understand this we must examine the local 
‘physiography a little more closely. From Carlisle it is hardly 
possible to obtain anything like just ideas upon the features that 
are essential in the present case. The true nature of the surface 
telief is best gathered from such points of view as the summits of 
the hills west of the Eden, especially from those between Lazonby 
‘and Penrith. Eastward from such a standpoint the general level 
of the broader features of the surface gradually declines until it 
‘merges into a gently undulating plain, which the eye can easily 
trace past Melmerby, Milburn, Dufton, and Murton to Brough, on 
he one hand; and, in the other direction can be as easily followed 
until it merges into the plain bordering on the Solway.* 
_ * This plain is the Third Plain of my former papers, and is probably of 
-Precretaceous age. 
