NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Artificial horizon question
From: Bill Morris
Date: 2009 Apr 20, 22:56 -0700
From: Bill Morris
Date: 2009 Apr 20, 22:56 -0700
Robert wrote (of mercury): "I agree with an earlier poster about mercury being ideal for stars. That being said, the stuff is hard to find, is highly toxic and therefore not recommended." The hazard from occasional handling of metallic mercury is probably negligible and small spills probably present no hazard from mercury vapour. It is poorly absorbed through the skin and it is very unlikely to find its way into the gut. Small amounts are efficiently excreted through the kidneys. An experimental observation of evaporation of two drops of mercury at room temperature by T. Winter in 2003 showed that the vapour levels were "small by comparison" with OSHA permissible exposure levels. Most compounds of mercury are very poorly soluble and present little hazard, but the same cannot be said of some organic compounds, notably dimethyl mercury, which is extremely toxic and can be absorbed through the skin as well as the gut. I am not advocating handling metallic mercury with gay abandon - it is too expensive and hard-to-find for that - but much more toxic substances can be found under the kitchen benches of most homes. And yes, I have some (a litre), and I handle it without afterwards having nightmares. Bill Morris Pukenui New Zealand --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---
