The lens was originally suspended in a basin of liquid mercury. While this provided a nearly frictionless way to turn the lens, it was also toxic. The mercury had to be drained and cleaned from time to time...
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| Eye to the Sea The lens was originally suspended in a basin of liquid mercury. While this provided a nearly frictionless way to turn the lens, it was also toxic. The mercury had to be drained and cleaned from time to time... |
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