636 
MR. A. W. RtiCKP^R AND DR. T. E. THORPE ON A MAGNETIC 
The mean of the Vertical Disturbances at the ten stations at Cromwell’s Hill and 
Kilteely is — 24 ; at the four stations furthest from the basalt + 48. 
The latter of these is higher than any Vertical Disturbance nearer than Nenagh, 
the former is higher than that at any neighbouring station except Tipperary, which 
is only 11 miles distant. 
The direction of the arrow at Tipperary also shows that the locus of attraction lies 
to the west of that place. 
On the whole, then, there can be no doubt that the ridge line passes, if not 
through the basalt, at all events very near to it. Further to the south it can be 
traced between Mitchelstovvn and Doneraile, near to a prominent maximum of 
A^ertical Disturbance at Cork, and thence to an unmistakable magnetic col at 
Bandon. 
The last ridge line which we include in the District of Mid-Ireland passes through 
Kells, which is, as we previously concluded, a magnetic peak. 
The region, of which this is the centre, is cut off from the rest of the District by a 
shallow magnetic valley, but on the whole we think the evidence of a connection 
between the Kells ridge line and the Slieve Bloom Mountains centre is so strong that 
we class them together. 
The Kells ridge line first appears in County Down at Annalong, and to which 
there are a number of stations of high Vertical Force. These may be more or less 
divided from the rest by a valley line between Dundalk and Castleblaney, but the 
directions of the arrows at those places and the high Vertical Force at Inniskeen, 
which lies between them, afford strong arguments against this vie\v. 
The ridge line runs between 
Dundrum and Annalong, which are .... 
Inniskeen ,, Dundalk ,, ,, . . . 
,, ,, Castle Bellingham, which are 
Kingscourt ,, Kells, which are .... 
Oldcastle ,, Athboy, which are. 
Street ,, Mullingar, which are . 
12 miles apart. 
7 ,, ,, 
10 ,, 
13 „ 
15 „ • „ 
14 „ 
Its position is therefore fixed at 6 points with an average uncertainty of 6 miles. 
The valley line referred to above connects Ballinasloe and Baltinglass. There is a 
magnetic col at Tullamore, and the directions of the Horizontal Disturbing Forces 
at Athlone and Tullamore, and, it may be added, at Mountrath and Parsonstown, 
confiiin the view that the ridge line under discussion is united with that which 
undoubtedly passes between the two last-named places. 
District 20.— Wexford. 
There is a centre of attraction in the extreme south-east corner of Ireland, 
including a station of very large Vertical Disturbance on the Saltee Islands. The 
