What is "speiss"

Speiss \Speiss\, n. [Cf. G. speise food, mixed metal for bells, etc.]

1. (Metal.) A regulus consisting essentially of nickel, obtained as a residue in fusing cobalt and nickel ores with silica and sodium carbonate to make smalt.

2. (Metal.) Impure metallic arsenides, principally of iron, produced in copper and lead smelting.

Speiss is a molten phase consisting primarily of iron arsenide that is commonly encountered in lead smelting operations.