Frankincense, a vegetable resin, brittle, glittering, and of a bitter taste, used for the purpose of sacrificial fumigation. Ex. 30:34-36. It was called frank because of the freeness with which, when burned, it gives forth its odor. It burns for a long time, with a steady flame. It is obtained by successive incisions in the bark of a tree called Arbor thuris. The first incision yields the purest and whitest resin, while the product of the after incisions is spotted with yellow, and loses its whiteness altogether as it becomes old. The Hebrews imported their frankincense from Arabia, Isa. 60:6; Jer. 6:20, and more particularly from Saba; but it is remarkable that at present the Arabian libanum or olibanum is of a very inferior kind, and that the finest frankincense imported into Turkey comes through Arabia from the islands of the Indian Archipelago. There can be little doubt that the tree which produces the Indian frankincense is the Boswellia serrata of Roxburgh, or Boswellia thurifera of Colebrooke, and bears some resemblance when young to the mountain ash. It grows to be forty feet high.