Hi Gordon, Sundialists Thanks for the info on "liquid mirrors"
I went out and looked around the net and found a few more references on the oil layer on top of the mercury. I have to apologize to all of you for not being able to provide more bibliographical information in my postings. Much of my old files showed up missing after the last physical move, and many of my disk files and articles were destroyed in each of the two major computer crashes in the last year. I did back up, but the tapes somehow were exposed to magnetic influences. I back up now on CDs so my records should be better in the future. I could not find the article about the synthetic oil with optimum damping/transparency properties, but I did recall that both castor oil and glycerin were both used quite successfully in damping out both random and rotary bearing vibration. They also reduced the release of mercury fumes. As I recall this preliminary work with oil damping of rotating mercury mirrors was done by Wood or Woods. I also recalled that the total apparent viscosity was also increased so that some tilting of the mirror was possible. Perhaps an over-lay of some particular oil might even damp the vibration in the water or wine mentioned by others here lately, as well as inhibit evaporation/algae growth. I'm in contact with a number of amateur lens/mirror grinders that are basically seeking to produce large high quality mirrors on the least expensive basis. I'll pass this on to them. Thanks again, Edley
