Forms: 6 lyȝtmose, lyt(t)mos(se, litmouce, 7 litmas(e, -mouse, litt(i)mus, 7–8 litmose, 8 litmoss, lytmus, 7– litmus. [Altered from MDu. leecmos, lijcmoes (mod.Du. lakmoes) LACMUS, prob. from association with LIT v.] A blue coloring matter, obtained from various lichens, esp. archil, Roccella tinctoria.
It is turned red by acids, and the blue colour is restored by alkalis.
1502. Receipt for Corke, in Arnolde’s Chron., 71 b/1. Take an C. & a q’rt of lyȝtmose.
1518. Will of R. Hoby (Somerset Ho.). xij bagges of Lytmos otherwise called white Corke.
1546. Inv. Ch. Goods Surrey, 107. Item for lyttmosse ijli. viijd.
1594. Plat, Jewell-ho., III. 37. Dry Litmas scraped in water.
1606. Peacham, Art of Drawing, 57. If you put to overmuch Litmose it maketh a deep blew.
1640. Rates, in Noorthouck, New Hist. London (1773), 838/2. Littimus, the cwt. qt. 112. lb. 1d.
1722. Act Encour. Silk Manuf., &c. in Lond. Gaz., No. 6040/7. Litmus the Hundred Weight,… twenty Shillings.
1811. A. T. Thomson, Lond. Disp. (1818), 471. This solution … reddens tincture of litmus.
1898. Allbutt’s Syst. Med., V. 448. Soak the papers in strong neutral litmus and dry them.
b. attrib., as litmus colo(u)r, liquor, tincture; litmus blue, a blue pigment prepared from litmus; litmus paper, unsized paper stained blue with litmus, to be used as a test for acids; when reddened by an acid, it serves as a test for alkalis.
1612. Peacham, Gentl. Exerc., 83. The principal blewes … are Blew bice, Smalt, *Litmose blew.
1727. W. Mather, Yng. Man’s Comp., 83. Put the quantity of a Hazel-Nut of Litmose-blue, to three Spoonfuls of Conduit-Water.
1805. W. Saunders, Min. Waters, 30. Another portion of the same *litmus liquor reserved for comparison.
1803. Davy, in Phil. Trans., XCIII. 246. A fluid came over, which reddened *litmus-paper.
1827. Faraday, Chem. Manip., xii. 270. Two of them [test papers] … surpass the rest, these are litmus and turmeric papers.
1899. Cagney, trans. Jaksch’s Clin. Diagn., vii. (ed. 4), 367. May’s *litmus tincture.
