roche alum

[ rohch ]

noun

, Chemistry.

1. an alumlike substance derived from alunite.

Word History and Origins

Origin of roche alum¹

1400–50; roche cliff, rocky height (now obsolete), late Middle English ( rock ¹ ); apparently partial translation of Middle French alum en roque, alun de roche

Example Sentences

Or, wash the brass-work with a strong solution of roche alum, and polish it with tripoli.

From Project Gutenberg

If one ounce of powdered roche-alum be put into a cask of four gallons of wine, it will make it fine and brisk in ten days.

From Project Gutenberg

A strong lye of roche alum and water also improves the appearance of brass.

From Project Gutenberg