BLACK-JACK, a kind of mineral found in the Derbyshire mines. It was some time ago employed in Wales for mending the roads; but is now found to answer the purpose of calamine for making brase.—Mons. Van Swab, in 1738, was the first person who distilled zinc from Black-jack; and it is said that some English manufacturers purchased the secret from him when he was in England; though they might possibly have taken the hint from a work which he erected for the purpose above mentioned.