Einstein and milk

[Kay Klein <k_klein@MV.MV.COM>]

I'm looking for a source for the story that Einstein supposedly told the
woman who asked him to explain the Theory of Relativity in simple terms.
It has to do with a blind man who was walking on a hot day and his companion
said he'd like to have a cold glass of milk.
If anyone knows where I can find this, I'd really appreciate a response.
I doubt that it should be posted to everyone, so just send your replies to
me: Kay Klein
    Bedford School District
    Bedford, NH
    k_klein@mv.mv.com

Thanks!