Schweinfurt Blue
:
ON THE PRIMARY, BLUE.
or Reboulleau's Blue, is prepared by fusing together equal weights of
ordinary arseniate of protoxide of copper and arseniate of potash, and
adding one-fifth its weight of nitre to the fused mass. The result is,
so to speak, a sort of blue Scheele's green, into which latter colour it
soon passes when rubbed with oil.