By at least 1117 AD, the Chinese used a magnetic needle that was submersed in a bowl of water, and would point in the southern cardinal direction.
22.
Massa is the first recorded town in Europe in which the magnetic needle compass was used in mines to map them and determine the extent of various mine owners'properties.
23.
The later maritime author Zhu Yu soon wrote of the magnetic needle compass as a means to navigate at sea, in his book " Pingzhou Table Talks " of 1119 AD.
24.
The mine, dropped from the air, would sink to the bottom of the river and sit there with its magnetic needle aligned to the Earth's magnetic field at that particular spot.
25.
Even before Shen Kuo and Zhu Yu had described the mariner's magnetic needle compass, the earlier military treatise of the " Wujing Zongyao " in 1044 had also described a thermoremanence compass.
26.
One instrument is a fish made of willow wood or pumpkin, into which a magnetic needle is inserted and which afterwards is sealed with tar or wax to prevent the penetration of water.
27.
During the trip to India, D . Jo�o de Castro has carried out a series of experiments that succeeded in detecting the phenomena, in particular related to magnetism and the magnetic needle on board.
28.
A circumferentor consists of a circular brass box containing a magnetic needle, which moves freely over a brass circle, or compass divided into 360 sights is located on the North-South axis of the compass.
29.
For example, the second book, " Mark the Mountain Guide and the Compass Adventure ", includes a working compass & brief illustrated explanations of the history, science & technique behind magnetic needles used for navigation.
30.
His design featured a metal compass capsule containing a magnetic needle with orienting marks mounted into a transparent protractor baseplate with a lubber line ( later called a " direction of travel indicator " ).
