92 
ME. C. V. WALKEE ON MAGNETIC STOEMS AND EAETH-CTJEEENTS. 
the studs were removed, and the needle allowed to go as far as the natural force could 
deflect it, we could increase that deflection by sending our usual currents in the proper 
direction ; so that if the studs are made to follow the needle into its new position, and 
are so placed that the needle shall be half-way between them, we can still get each kind 
of deflection,” &c. — P. 67. 
I then go on to describe how I mounted the studs and made them movable. Imme- 
diate steps were taken to apply this adjustment to the existing instruments. Matters 
looked so serious at the time that further steps were taken. I made the coils of the 
galvanometers movable round their centre ; and, when the needles were disturbed, moved 
the coils after them, as when using a sine-galvanometer, until the needle was midway 
between the studs and in the centre of the coil, although of course no longer vertical. 
We were soon, however, as much surprised by the disappearance of these distm’b- 
ances, as we had originally been by their appearance. Our arrangements for adjusting 
the needles were scarcely carried out when the necessity for the alterations began to 
disappear. Again quoting the words which conveyed our then impressions : — “ 86. It 
is most remarkable that during the year 1849 these deflections were rare and trmal, 
whereas in 1847 and 1848 they occurred many times on the main line, v and were of 
almost daily occurrence on the Ramsgate branch, and to such an extent that the instru- 
ments required unusual precautions to enable them to give signals .” — Electric Telegraiili 
Manipulation, p. 67. 
This state of things still continued to March 1, 1850, when the remarks just quoted 
were pubhshed ; and a considerable period subsequently elapsed before any change for 
the worse (speakhig technically) occurred ; and this will account, in great measure, for 
the question ha\dng so long lain dormant. We did not then know, as we now do, that 
these disturbances have a cycle of about eleven years from the maximum period of 
acthity to the next maximum, and that they go with the magnetic disturbances. It 
seemed at the time as if we had passed out of an abnormal state, which had left no 
evidence behind of its probable return at some distant period. 
The “ unusual precautions” referred to in the last extract, over and above the adjust 
ments applied to the instruments themselves, were : — detaching the earth-wire at the 
respective termini of the Ramsgate branch line of telegraphs; converting the double 
needle into a single needle communication ; employing the wire released from one needle 
as the retm n wire for the circuit of the needle retained. When the telegraph was thus 
cut olT from all communication with the earth the disturbances ceased. 
In the ‘ Philosophical Transactions ’ for the year 1849, is a paper by W. H. Barlow, 
Esq., “ On the Spontaneous Electrical Currents observed in the Wires of the Electric 
Telegraph,” which was read on May 25, 1848. The author not only records the simul- 
taneous disturbances observed by him of the magnets, and of the telegraph galvanome- 
ters on September 24 and 25, and October 23, 24, and 25, 1847, but he describes also an 
original and very interesting set of experiments made by him at Derby upon various tele- 
graph routes centrmg in that station. He regarded the stations in then- absolute bearing 
