Sugar treacle. The word appears as Melasus, Molassos, Malassos, Molossos, Molossus: see examples 1592–1694, N.E.D.

1

1705.  [They] observ’d an inspissate Juice, like Molasses, distilling from the Tree.—Beverley, ‘Virginia,’ ii. 21.

2

1765.  It is bartered in the French and Dutch colonies for melasses.Boston-Gazette, May 27.

3

1777.  I have seen some of the melasses from corn-stalks…. I would advise every person that makes melasses this way, &c.—Maryland Journal, Dec. 2.

4

1789.  If a merchant cheated in a bushel of salt or a gallon of melasses, the consequences were hardly perceptible.—American Museum, v. 46/2 (Jan.).

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