Metallic tungsten may also be obtained by the reduction of tungstic acid, by means of charcoal at a white heat.
It is weighed when cold, and is the trioxide or "tungstic acid" (WO3), which contains 79.31 per cent.
tungstic acid gives a dark yellow clear bead while hot, but is opaque and yellow when cold.
Next followed the discovery of tungstic acid, and in 1783 he added to his list of useful discoveries that of glycerine.
tungstic acid may be got into solution after fusion with alkalies or alkaline carbonates.
“Now,” he said, when the tungstic acid had been dissolved, and he had dropped a small bar of tin into the solution.