This beautiful fluid compas is one of the may items in the museums collection. The presence of fluid acts to damp the horizontal circular oscillation of a compass card and allows the card to settle on north much faster than air-damped compasses. Liquid-damped compasses traditionally have a floating compass dial that turns instead of a moving needle supported over a fixed card.
A special compas oil is used these days, alcohol, e.g. Gin, was used by ancient mariners if nothing else was at hand, purified kerosene has also been used. The opinions on what is best, seem to be as varied as the oils and alcohols available.
WARNING. As beautiful as these old compases are, some can be very dangerous, those manufactured between 1904 and the 1960s could contain the highly dangerous radioactive element Radium. The Radium was used in the paint to give it luminocity, the fluid around the paint would also be radioactive after many years of contact with the Radium.
These types of compases should only be opened by qualified persons.
If inhaled or entry into the body through a cut, it would be wise to seek urgent medical help.
Read More (http://www.trademarklondon.com/Compass-Fluid/index.html )
|
No comments :
Post a Comment