106 
ME. C. V. WALKEE ON MAGNETIC STOEMS AND EAETH-CUEEENTS. 
vacant space, we should no doubt have been able to present results from lines situate 
either beyond No. 26 on the one hand, or beyond No. 23 on the other, and have con- 
tracted still more the range, now standing at 31°. 
In the absence of these observations, we are still justified in concluding that neither 
No. 26 on the one hand, nor No. 23 on the other, are the boundary lines, because, 
when we look at the eight cases before us, four have strong currents in both limiting 
lines, and one has mry strong ; and if we turn back to sections 1 and 2 of Table XII., 
fourteen out of the eighteen cases have strong or very strong currents in the London — 
Dover boundary line. 
Subject to correction by future observations, I have assumed that 10° may reasonably 
be allowed in each direction, making 20° in all to be deducted from 31°, leaving a limit 
of only 11° within which to seek for the true direction. For the place of this limiting 
arc, we have 
90 — 44+10 =56 E. of N. ; the northern limit. 
90 — (13+10}=67 E. of N. ; the southern limit. 
11 ; the total range. 
Its place is shown by the more deeply shaded part of fig. 5. From finding the London 
— Dover line (No. 25-26) the more active, I should be disposed to infer the true direc- 
tion to be nearer the Dover — London than the London — Tonbridge hue ; and to divide 
the 11° unequally. Making the proportion as 7° to 4°, we have 
56 + 7 = 63 E. of Mag. N.l 
[true direction. 
67-4=63 E. of Mag. N.J 
This du’ection is shoum by the arrow R R' in fig. 5, Plate III. And by deducting from 
this the magnetic declination of 21;!^°, we have 63° — 21+=41f° E. of N. as the true 
geographical bearing of the point whence these earth-currents flow when in one direction, 
and 41|-° W. of S. when in the other direction. And there is no evidence that they exist 
in other azimuths. We are not in a condition to detect secular changes, if any, as there 
may be. They would possibly be small ; and our range in respect to such probable 
changes is large. For three years at least their direction has not greatly varied, at least 
so far as the south-eastern counties of England are concerned. The greater may contain 
the less ; but I would pause before inferring the greater from the less, and contending 
that what is true of the small dot of the earth which has been the subject of my 
observations, may be equally true of the rest of Europe, to go no further, or even of 
the rest of this little island. 
The contents of the reports referred to above, of the disturbances of Aug.-Sept. 
1859, are too concise to contain materials from which the probable direction of the earth- 
currents elsewhere may be determined with accuracy. But the little information they 
contain helps for the most part to confirm the conclusions to which we have arrived, 
