Mercury Seal
The first technological use of a glass-to-metal seal was the encapsulation of the vacuum in the barometer by Torricelli. The liquid mercury wets the glass and thus provides for a vacuum tight seal. Liquid mercury was also used to seal the metal leads of early mercury arc lamps into the fused silica bulbs.
A less toxic and more expensive alternative to mercury is gallium.
Mercury and gallium seals can be used for vacuum-sealing rotary shafts.
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Famous quotes containing the words mercury and/or seal:
“The mercury sank in the mouth of the dying day.
What instruments we have agree
The day of his death was a dark cold day.”
—W.H. (Wystan Hugh)
“The denial of our duty to act in this case is a denial of our right to act; and if we have no right to act, then may we well be termed “the white slaves of the North,” for like our brethren in bonds, we must seal our lips in silence and despair.”
—Angelina Grimké (1805–1879)