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VII. On Magnetic Storms and Earth-Currents. 
By Chaeles V. Walkee, Esg., F.B.S., F.R.A.S. 
Eeceived January 31, — Bead February 14, 1861. 
DiSTUEBAJ!fCES of the needles of the electric telegraph were noticed very soon after t^e 
completion of the first working lines. They were at once seen to be due to causes 
exterior to the apparatus itself. 
On Saturday, May 8, 1847, I find the following entry in my diary: — “At Tonbridge. 
Through. instrument needles stood at ‘wait’ from 5.6 to 5.10, and hung when turned 
to Dover; all right when turned to London. From 6.4 to 6.19 they hung to ‘go on ’ 
on the down side. The Maidstone needles also hung.” 
On Friday, September 24 : — “ Singular atmospheric day. All over the line, and in 
all the groups, needles were strongly affected between noon and midnight. Signals 
could hardly be made. Bells rang. The deflections varied. Sometimes the up-side 
deflections dififered from the down. Memorandum for Tonbridge. — 12.50 turned down, 
needles at E.N. ; 1 p.m., vertical; 1.5, at E.N. ; 1.11, +H; 1.14, vertical; 1.15, E.N. 
hard up ; 1.17, vertical ; 1.18, E.N. ; 1.23, vertical. During some parts of day through- 
beUs rang. At night evidently an extensive aurora ; but being full harvest moon and 
clear, not very conspicuous.” 
On Saturday, October 23: — “Needles hung. Wind S.W. gale; driving rain; low 
hea\'y clouds ; continued unfair ; signals much retarded. This continued more or less 
during day and night, of which I have a series of notes made at Tonbridge. The needles 
were occasionally aflected during Sunday; and at night there was a splendid aurora 
visible, in spite of the full moon. The sudden transitions from right to left were 
remarkable.” 
On Monday, October 25 : — “ The needles affected a little this morning. At 10.1 a m. 
the needles went over suddenly to W. ; and in the next minute changed as suddenly 
to K.” 
I copy these notes just as they stand recorded. They are expressed in the technical 
language of telegraphy. I shall have no occasion to refer back to them for illustration, 
as we have observations of recent date, carried on for long periods and under regulation, 
so that it is not necessary to occupy time in putting the above into common language, 
further than to say that when the telegraph needles are deflected to the right hand 
they make E.N. or R, or “ wait ;” and when deflected to the left, they make +H or W, 
or “go on;” and that a positive current passing in the telegraph wires from Dover to 
London causes a right-hand deflection, and one from London to Dover a left hand. 
MDCCCLXI. 0 
