pearl-ash
(ˈpɜːlˌæʃ)
The potassium carbonate of commerce, so called from its pearly hue. Orig. only in pl. pearl ashes.
| α 1727–41 Chambers Cycl. s.v. Ashes,..divers sorts of ashes imported from abroad: as pot-ashes, pearl-ashes. 1776 J. Clegg in T. Percival Ess. III. App. 335 Into one vessel I put a small quantity of pearl ashes. 1811 A. T. Thomson Lond. Disp. (1818) 321 It assumes a spongy texture, with a blueish or greenish colour, and is then denominated pearl-ashes. |
| β 1765 Croker, etc. Dict. Arts & Sc. s.v. Pot-ash, The purity of pearl-ash..points out the method in which it has been prepared. 1796 Kirwan Elem. Min. (ed. 2) II. 269 Take one part of the roasted Ore, 3 of Pearl Ash. 1866 Roscoe Elem. Chem. 160 This is the crude potassium carbonate, called, when purified by re-crystallization, pearl-ash. |