I^IE. C. V. WALKEE ON MAGNETIC STOEMS AND EAETH-CUEEENTS. 
95 
the latter method having been more available since the custom of fishing or connecting 
the consecutive rails together with a plate of iron has prevailed. The electricity col- 
lected from the earth by these probes or earth-plates appears in our wires as a derived 
current. It enters a wire at the station nearest to the point of the horizon /rom which 
the current is flowing, and leaves it at the station nearest to the point of the horizon 
toward which it is flowing. In Table XI. the direct distances between the respective 
terminal stations are given in the fourth column, and the telegraph distances in the 
fifth. A few cases occur in which the difference is considerable, which is when the 
railway route is circuitous. I may state here that the reason why the Margate — ^Ashford 
telegraph route is nearly double that of the direct route, is because the wires make a 
loop to Deal, and thence vid Eamsgate to Margate. The effect of this extra length of 
wire being between the respective earth-plates is, of course, from the increase of resist- 
ance, to diminish the value of the derived current. The Margate— Ashford is, as we 
shall see hereafter, our most active circuit ; it would show values still higher were the 
connecting wire in a direct line. 
I regretted to find that the returns which reached me of the telegraph disturbances 
of August — September 1859 were unusually meagre. The fact appears to have been 
that the distmhance was of such magnitude and of so long continuance, and this at the 
busy season when the telegraph is more than usually required, that our clerks were at 
their wit’s end to clear off the telegrams (which accumulated in their hands) by other 
less affected but less direct routes. At a time when observations would have been very 
highly acceptable, they were too much occupied with their ordinary duties to make 
notes of the deflection of the needles and the changes. And I may here advert to the 
circumstances with which we are surrounded, and the conditions under which our 
observ'ations are made. The wires and telegraph instruments are erected for com- 
mercial purposes ; they are, as a rule, very fully occupied. The clerks or employes in 
charge of the instruments have their various duties to discharge, and have not much 
time at their command. I am on this account the more indebted to them for the 
interest they have evinced in these observations, and the unusual diligence with which 
some of them have made notes of what they have seen. And I may especially refer to 
J. Dyke at Ashford, D. Malpas at Eamsgate and T. Pulley at Eamsgate, and then at 
Canterbury. They have proved themselves able volunteers in the cause of science. 
The Astronomer Eoyal, in his “Eeport to the Board of Visitors,” on June 2, I860, 
says “ it is extremely difficult to extract from the accounts, even the careful ones, of 
telegraph clerks, such an idea of the phases of the currents as will make them com- 
parable with the phases of magnetic storms.” I can well enter into Mr. Airy’s views; 
and if I plead guilty to having not furnished him with observations made on my district, 
to compare with the other observations that have reached him, it is because I have not 
heretofore had the opportunity of fairly discussing the crude facts that have accumulated 
in my hands. He further adds that “ it may be worth considering whether it would 
ever be desirable to establish in two directions at right angles to each other (for instance, 
