OBSERVED IN THE WIRES OF THE ELECTRIC TELEGRAPH. 
67 
The observ’ations were made with galvanometers on two or more wires simulta- 
neously, and the motions of the needles observed for several hours. It frequently 
happens that, from some difference in the earth connection, there is a slight perma- 
nent action, so that in making these observations it is not simply the position but 
the motion of the needles that distinguishes the direction of the current. If on try- 
ing two wires, one causes the galvanometer needle to move from right to left, when 
the other moves from left to right, the currents are in opposite directions. 
Mr. CuLLEY has favoured me with another set of observations obtained from the 
telegraph instruments at Normanton, during large deflections. 
Normanton is a central station from which seven telegraphs branch off. Each 
telegraph has an earth connection at Normanton, and the other extremities of the 
telegraphs are connected with the earth at Rugby, Derby, Manchester, Leeds, New- 
castle, York and Hull. 
Calling those telegraphs in which the deflections accord with that to Manchester 
-f, the results are as follows ; — 
From Normanton to Rugby. . . S. 5° E. + 
From Normanton to Derby . . . S. 2° W. -f- 
From Normanton to Manchester . S. 65® W. -j- 
From Normanton to Leeds . . . N. 35° W. doubtful — , very small deflections. 
From Normanton to Newcastle . N. 8° W. doubtful, generally — . 
From Normanton to York . . . N. 40° E. — 
From Normanton to Hull . . . N. 87° E. — 
The general result derived from these two sets of experiments may be stated as 
follows ; — Taking one earth connection as a point of reference when the bearing of 
the other earth connection lies between S. and W., or between N. and E., the action 
is strong and decided, the one being -f- and the other — . 
In the experiments made from Derby as a central point, the action of the current 
is reversed when the earth connection is changed from S. 15° E. to S. 62° E. I have 
tried numerous experiments between these two directions, and there does not appear 
to be any line in which all action ceases, but in approaching the S.E. direction the 
motion of the needles becomes undefined. 
The direction in which the currents travel being supposed to be at right angles to 
that in which the reversed action takes place, will be between S. 28° W. and S. 76° W., 
and apparently strongest when the earth connections are about N.E. and S.W. 
As the fact above mentioned, namely, that the direction of the current in any wire 
at a given time depends on the relative positions of the earth connections, and not 
on the direction of the wire itself, is of great interest, I have recently repeated some 
of the observations on this subject, the results of which are given in diagram No. 3. 
In these observations, a spare wire from Derby to Willington, length 6^ miles, 
bearing S.W., was used as a standard of comparison, and simultaneous observations 
were made on it, and on a wire from Derby to Rugby, varying the position of one of 
the earth connections of the Rugby wire as described below. 
