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    Re: Children's land-locked "Sextant"
    From: Geoffrey Kolbe
    Date: 2007 Nov 28, 21:08 +0000

    Gary LaPook wrote:-
    
    
    >With use it develops a dross floating on the surface which can be
    >removed by filtering it through a piece of cloth like an old t-shirt.
    >You have to twist the cloth to force the mercury though the cloth and
    >it comes though in shiny little balls leaving the dross in the cloth
    >which I then dispose of. You should probibly wear gloves when handling
    >the mercury like this.
    
    In the 1960's the old Royal College of Science in London was pulled down to
    build Imperial College, the British attempt to emulate MIT in the United
    States.
    
    The Spectroscopy labs in the RCS had long been plagued with the problem
    that continuum spectra always had absorption lines of mercury on them. On
    taking up the parquet floor in the lab, a veritable lake of mercury was
    found underneath! As far as I know, all the researchers of that era lived
    to a ripe old age, despite working for many years in an environment where
    the mercury vapour in the air was probably at saturation point.
    
    Not that I am advocating that we should not take suitable precautions when
    using poisonous substances like mercury - its just that people somehow seem
    to be more susceptible to such things than they used to be in times
    past.... or, at least, that is the perception.
    
    Geoffrey Kolbe
    
    
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