Shark Oil Barometers
Shark (liver) oil barometers are used to forecast weather. In particular, Bermudians have used them for "hundreds of years" to forecast tropical storms. Very little is known about how shark oil barometers work. I purchased mine in the summer of 2003 (I think) during a trip to Bermuda. I gave it to my son as a gift. Effectively, it is on loan from him. It is shown as the backdrop of the central weather summary on my home page, Stu-in-Flag.net
Also, a very small picture of the actual glass barometer portion is the icon for the bullets on the menu to the left.
The two pictures below are from the hang-tag that was attached to it when I purchased it. This hang tag tells almost as much of the story as you can find anywhere on the internet. From changes in pressure and humidity, to changes in electrical activity, there are many rumors for why they are clear with good weather, and cloudy with bad weather.
I have had mine on my dresser in my bedroom for years. It never seemed to change much, unless a particularly severe storm came to Northern Arizona. It did not receive much natural light. Recently, I moved it to a window that allows plenty of natural light, and some direct sunshine to reach it. The result is that it came to life immediately. The picture above shows how it is cloudy just before the first snow storm of the 2008-2009 Winter. I am going to start to add comments in the blog based on how clear or cloudy the shark oil is.