When I was a boy scientist I loved mercury. I had a few pounds of it in my bedroom and used to push little balls of it around, until it got lost between the floorboards. For a high school science fair I built an ion drive spaceship engine where I vaporized it, ionized it, and accelerated it through magnetic fields. This could only happen in a vacuum, so I had a mercury diffusion pump. Now I learn that "it’s a neuro-toxin linked to all sorts of things we could do without, like impaired memory, motor skills and learning disabilities." This explains a lot. Today, most sources of liquid mercury, from silent switches to thermometers, are banned, and the worst sources are coal fired power plants (don't look for any relief there in the near future) and fish. Got Mercury? is an online calculator where you enter your choice of fish, the number of times you eat it per week, and determines your exposure as a percentage or the EPA limit. If only we had known. ::Got Mercury? via ::Urbaneco