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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Artificial Horizons and Tea
From: Trevor Kenchington
Date: 2003 Jul 11, 21:11 -0300
From: Trevor Kenchington
Date: 2003 Jul 11, 21:11 -0300
Thanks to Phil Guerra for the two Web links. I guess our childhood playing with liquid mercury wasn't a great idea but many of us have done it and few seem to show much in the way of symptoms. Phil's first link led to a page that points out the extreme toxicity of methyl mercury (the very nasty organic compounds), the dangers of a number of inorganic mercury compounds, and the nasty consequences of inhaling gaseous mercury -- such as you might get from heating the liquid form. But nothing there suggests significant toxicity from the unheated liquid if you were using it in an artificial horizon out of doors and didn't stick your face right over the surface. There is some good advice: * Do not eat, drink, or smoke; or store food, drinks, smoking materials, or cosmetics in areas where mercury is in use. * Avoid skin and eye contact. Use rubber or plastic gloves when handling metallic mercury * Wash hands and face after handling mercury, before lunch or breaks, and at the end of the work day. * Transfer of liquid mercury between containers should be carried out over a tray or pan to confine any spills. And so on. You would, however, also be well advised to take those same precautions if your preference in an artificial horizon is used engine oil. Phil's second link also emphasized the dangers of inhaled gaseous mercury. It also included two rhetorical questions and an answer: "I have mercury amalgams in my dental work. Am I slowly being poisoned? Should I have them removed? You are not being poisoned. Elemental mercury absorption in the gastrointestinal tract is negligible, particularly in the relatively small quantities generated from dental amalgams. For children and women of childbearing age, a physician should be consulted." I'm no chemist and I have no medical training, so only a fool would follow my guidance on this point. But it looks to me that a mercury artificial horizon, handled with reasonable care, is not likely to cause you serious harm. If anything, the suggestion of using Scotch in winter conditions sounds more risky: It would be a crime to waste even a drop but downing the entire contents of a pie plate after each observing session could markedly shorten your life -- no matter how pleasant the experience! So, to repeat George's question: Is it possible for a member of the general public to buy elemental mercury in the quantity needed for an artificial horizon? Trevor Kenchington -- Trevor J. Kenchington PhD Gadus@iStar.ca Gadus Associates, Office(902) 889-9250 R.R.#1, Musquodoboit Harbour, Fax (902) 889-9251 Nova Scotia B0J 2L0, CANADA Home (902) 889-3555 Science Serving the Fisheries http://home.istar.ca/~gadus