scorias

Tests made from this standpoint at the works of Mansfield have shown that the addition of 0.45 per cent. of cupro-manganese is sufficient to give tenacity to the copper, which, thus treated, will not contain more than 0.005 to 0.022 of oxygen, the excess passing off with the manganese into the scorias.

Scientific American Supplement, No. 315, January 14, 1882 Various

Pillars of smoke and flame escaped from the crater; a hail of scorias fell on the ground; but no current of lava burst from the mouth of the volcano, which proved that the volcanic matter had not yet attained the level of the superior orifice of the central shaft.

The Secret of the Island Jules Verne 1866