How to use Dipping-needle in a sentence
Gilbert in 1600, that the earth itself is a great magnet, having its poles at the two places where the dipping needle is vertical.
Attached to the cross-arm which carries the microscopes used to observe the ends of the dipping needle is a clamp, which will hold the needle b in such a way that its plane is parallel to the vertical circle and its axis is at right angles to the line joining the two microscopes.
Hence, when the microscopes are adjusted so as to coincide with the points of the dipping needle a, the axes of the two needles must be at right angles.
This seems in general to be nearly coincident with the direction of the dipping needle.Advertisement