Manna

A gum, or honey-like juice concreted into a solid form, seldom so dry but it adheres to the fingers: its color is whitish, or brownish, and it has sweetness, and with it a sharpness that renders it agreeable: manna is the product of two different trees, both varieties of the ash: when the heats are free from rain, these trees exudate a white juice. It is but lately that the world were convinced of the mistake of manna being an aerial produce, by covering a tree with sheets in the manna season, and the finding as much manna on it as on those which were open to the air. [Johnson's Dictionary, 9th Edition, 1806]