JACK O' LANTERN. The corpo santo, or St. Elmo's light, is sometimes so called.
JACK-PINS. A name applied to the fife-rail pins, also called Tack-pins.
JACK ROBINSON.—Before you could say Jack Robinson, is a very old expression for a short time,—
"A warke it ys as easie to be doone,
As tys to saye Jacke Robyson."
JACK'S ALIVE. A once popular sea-port dance.
JACK-SCREW. A small machine used to cant or lift weighty substances, and in stowing cotton or other elastic goods. It consists of a wooden frame containing cogged iron wheels of increasing powers. The outer one, which moves the rest, is put in motion by a winch on the outside, and is called either single or double, according to its increasing force. The pinions act upon an iron bar called the spear.
JACK-SHARK. A common sobriquet of the Squalus tribe.
JACK-SHARP. A small fresh-water fish, otherwise known as prickly-back.
JACK'S QUARTER-DECK. The deck elevation forward in some vessels, often called a top-gallant forecastle.
JACK-STAFF. A short staff raised at the bowsprit-cap, upon which the union-jack is hoisted.