roche alum
(rəʊtʃ ˈæləm)
Also 5 rooch, 5–9 roch, 7–8 roach.
[f. roche n.1 + alum n., after F. alun de roche (cf. alun en roque, 1368), It. allume di rocca: cf. Du. rotsaluin, G. rotsalaun, and the synonymous Sp. piedra alumbre, Pg. pedra (a)hume.
The statement that the name is derived from Roccha, a Turkish province in N. Syria, is evidently quite unfounded.]
= Rock alum (see alum n. 1).
| α 1436 Libel Eng. Policy in Pol. Poems (Rolls) II. 172 They bringe wyth hem..Coton, roche-alum, and gode golde of Jene. 1453 in Heath Grocers' Comp. (1869) 422 Alum, foyle or rooch, ye bale, iiijd. 1597 Lowe Chirurg. Y 4 b, Betonie, worme-wood, roch allom. 1601 Holland Pliny II. 165 Seeth the same..together with Safron, Roch-allom, Myrrh, and the best Attick hony. 1669 Sturmy Mariner's Mag. vii. xxxiv. 50 Put in it the bigness of a Hens Egg of Roch Allom. 1747 Wesley Prim. Physick (1762) 42 Make a Plaister of Roch Allum, Vinegar and Honey. 1753 J. Bartlet Gentl. Farriery (1754) 190 Giving drinks prepared with green vitriol, roch allum, Roman vitriol. 1853 Ure Dict. Arts (ed. 4) I. 57 The mother liquor of the ‘roch alum’ is called ‘tun liquor’. 1860 [see rock alum]. |
| β 1619 E. Bert Hawkes 84 Seeth some spring water, and..put into it a peece of Roach-Allum. 1620 Observ. Silkwormes D j b, Roach Allum, called Romish Allum. 1704 Lond. Gaz. No. 4008/4 Roach-Allum, Coffee, Brimstone. 1753 Chambers Cycl. Suppl. s.v. Phosphorus fæcalis, Mix it with the same quantity of roach alum grossly powdered. 1799 G. Smith Laboratory II. 401 Together with..half a pound of roach alum, &c. |