formerly among the Scotch Highlanders when a chieftain desired to summon his clan he slew a goat and, making a cross of any light wood, seared its extremities in fire, and extinguished them in the blood of the animal. This was called the fiery cross, also creau tarigh, or the cross of shame, because disobedience to the symbol inferred infamy. It was delivered to a messenger, who ran with it to the next hamlet, where he presented it to the principal person, with a single word, the place of rendezvous. He who received the symbol was bound to send it forward to the next village; and thus it passed through all the district. At the sight of the fiery cross, every man, capable of bearing arms, was obliged to repair to the place of rendezvous. He who failed to appear, suffered the extremities of fire and sword.
Entry from Everybody's Cyclopedia