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Rh galvanometer, but this current will go in an opposite direction to that which circulates round the right-hand coil.

103. Again, as long as the current continues to flow through the right-hand coil there will be no current through the other, but at the moment of breaking the contact between the right-hand coil and the battery there will again be a momentary current in the left-hand coil, but this time in the same direction as that of the right-hand coil, instead of being, as before, in the opposite direction. In other words, when contact is made in the right-hand coil, there is a momentary current in the left-hand coil, but in an opposite direction to that in the right, while, when contact is broken in the right-hand coil, there is a momentary current in the left-hand coil in the same direction as that in the right.

104. In order to exemplify this induction of currents, it is not even necessary to make and break the current in the right-hand coil, for we may keep it constantly going and arrange so as to make the right-hand coil (always retaining its connection with the battery) alternately approach and recede from the other; when it approaches the other, the effect produced will be the same as when the contact was made in the above experiment—that is to say, we shall have an induced current in an opposite direction to that of the primary, while, when it recedes from the other, we shall have a current in the same direction as that of the primary.