Several of the varieties are cut into gems and ornaments, balance weights, pivot supports for delicate instruments, agate mortars, &c.; or used for engraving, for instance, cameos and the elaborately carved crystal vases of ancient and medieval times.
The most primitive is the rubbing together of the concentrated crushings with mercury in iron mortars.
This, he imagined, would compel an assailant to maintain large forces in the advanced trenches, which he proposed to attack by vertical fire from mortars.
Between Monte Rombon and Monte San Gabriele,, Capello had some 2,200 guns and nearly Boo trench mortars.
More than 3,000 guns had been lost, and over 1,700 trench mortars.