On one side The Pass was flanked by the Bubbling Zinc Pits and on the other side it was skirted by the fluoride River, and man had not yet devised any way to navigate either of these.
"The Wealth of Echindul"
Noel Miller Loomis
While the arcs with plain carbons are bluish-white, those with carbons containing calcium fluoride have a notable golden glow.
"Edison, His Life and Inventions"
Frank Lewis Dyer and Thomas Commerford Martin
But the use of sulphites in sausage and chopped meat, the addition of formaldehyde to milk, and of boric acid or sodium fluoride to butter are practices altogether objectionable from the standpoint of public health.
"Food Poisoning"
Edwin Oakes Jordan