In operation, the instrument is first rotated until the magnetic field of the Earth, indicated by the compass needle, is parallel with the plane of the coil.
32.
A magnetic line of force is what a freely gimbaled compass needle would align with-and what a not quite free needle " tries " to align with.
33.
Afterward, compass needles that normally point north would point south, and during the thousands of years of transition much in the heavens and Earth would go askew.
34.
It was Hans Christian �rsted who first proposed the connection between electricity and magnetism after observing the deflection of a compass needle by a nearby electric current.
35.
If you put a compass onto the table and spin a magnet around or wave it about in some way-then the compass needle will also move around.
36.
The compass needle is just a little magnet that lines up with the magnetic field lines of Earth; these imaginary lines converge on a spot near Greenland.
37.
The compass needle responds to the vector sum of the two fields, and deflects to an angle equal to the tangent of the ratio of the two fields.
38.
Thomson's design, was able to detect very rapid current changes, by using small magnets attached to a lightweight mirror, suspended by a thread, instead of a compass needle.
39.
At the White House, meanwhile, the compass needle swung from the ceremonial triumph of the speech to the touchy legal matter of the first lady's grand jury appearance Friday.
40.
His work is particularly noted for containing the earliest detailed discussion of freely pivoting compass needles, a fundamental component of the dry compass soon to appear in medieval navigation.
