A proportion used in determining the dimensional relationship of a representation to that which it represents: a world map with a scale of 1:4,560,000. b. A calibrated line, as on a map or an architectural plan, indicating such a proportion.
Yttria (yttrium oxide, Y 2 O 3), was discovered by Johann Gadolin in 1794 in a mineral called gadolinite from Ytterby. Ytterby is the site of a quarry in Sweden which contains many unusual minerals containing erbium, terbium, and ytterbium as well as yttrium.
He found it contained 31% silica, 19% alumina, 12% iron oxide and 38% of an unknown earth. (3) Gadolinâs results were confirmed in 1797 by Swedish chemist Anders Ekeberg. Ekeberg suggested the name yttria for the oxide of the new earth metal and hence the new metal was named yttrium.