It consist of two equal coaxial coils (parallel to each other) separated
by
distance equal to the radius of the coils. The magnetic compass is
pivoted on the brass cup at the midway between them and
the same
current is passed through the coils in the same direction. The coils
increase the uniformity of the field at
the middle and thus make it
more sensitive. Supplied with superior quality Magnetic
Compass
box.