The growing use of tungsten in high speed steels and for electrical purposes makes it increasingly desirable to include this element in the scheme of analysis. Metallic tungsten is seldom if ever found in nature, but occurs in several well-crystallized tungsten minerals of which Scheelite, CaW04 , is typical. From its position in the periodic table, Group VI - Series 6, one should expect tungsten to have amphoteric properties. Although we are more familiar with tungsten in the metallic state, it almost invariably behaves as a non-metal in chemical combination. For this reason in analytical work tungsten naturally falls among the anions
