image source:
McGill library
rare books – special collection
McLennan building 4
Z 6616 L58 R47 1974 V1
Codex Madrid, Leonardo da Vinci
book 1, page 13 verso
“The Madrid Codices I–II (I – Ms. 8937 i II – Ms. 8936), are two manuscripts by Leonardo da Vinci which were discovered in the Biblioteca Nacional de España in Madrid in 1964.”
Beside the sketch, Leonardo wrote:
“method of making rings which can turn in every direction such as the mariner’s compass.”
After researching, I found out that the actual name of this instrument is a Guimbal and that Leonardo did not invent it.
The design consists of a “system of rings enables the inner hemisphere to keep its original position independently of its rotation. Two ring pivots fix the three outer rings to each other as they rotate, with a 90° displacement between each pair of rings. In this way, the inner system can move freely on three axes (X, Y, Z). The weight beneath the rotational axis keeps the inner hemisphere horizontal. The same system had always been used on ships to hold oil lamps steady in spite of the pitching caused by waves.”
I firstly want to work on this topic because I find the mechanism beautifull and fascinating. Secondly, it is very relevant to our two first assignments.
In itself, the object is useless as it has to work with something on the inner ring. Therefore, I am willing to build an old fashionned compass to complete it.
http://www.leonardo3.net/leonardo/machines_eng.php
http://en.wikipedia.org/wiki/Gimbal