E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Gabel, Gabelle (g hard).
A salttax. A word applied in French history to the monopoly of salt. All the salt made in France had to be brought to the royal warehouses, and was there sold at a price fixed by the Government. The iniquity was that some provinces had to pay twice as much as others. Edward III. jokingly called this monopoly King Philippes Salic law. It was abolished in 1789. (German, gabe, a tax.)