資料來源 : Webster's Revised Unabridged Dictionary (1913)
Litmus \Lit"mus\, n. [D. lakmoes; lak lacker + moes a thick
preparation of fruit, pap, prob. akin to E. meat: cf. G.
lackmus. See {Lac} a resinous substance.] (Chem.)
A dyestuff extracted from certain lichens ({Roccella
tinctoria}, {Lecanora tartarea}, etc.), as a blue amorphous
mass which consists of a compound of the alkaline carbonates
with certain coloring matters related to orcin and orcein.
Note: Litmus is used as a dye, and being turned red by acids
and restored to its blue color by alkalies, is a common
indicator or test for acidity and alkalinity.
{Litmus paper} (Chem.), unsized paper saturated with blue or
red litmus, -- used in testing for acids or alkalies.
Cudbear \Cud"bear`\ (k?d"b?r`), n. [Also {cudbeard}, corrupted
fr. the name of Dr. Cuthbert Gordon, a Scotchman, who first
brought it into notice.]
1. A powder of a violet red color, difficult to moisten with
water, used for making violet or purple dye. It is
prepared from certain species of lichen, especially
{Lecanora tartarea}. --Ure.
2. (Bot.) A lichen ({Lecanora tartarea}), from which the
powder is obtained.
Cudbear \Cud"bear`\ (k?d"b?r`), n. [Also {cudbeard}, corrupted
fr. the name of Dr. Cuthbert Gordon, a Scotchman, who first
brought it into notice.]
1. A powder of a violet red color, difficult to moisten with
water, used for making violet or purple dye. It is
prepared from certain species of lichen, especially
{Lecanora tartarea}. --Ure.
2. (Bot.) A lichen ({Lecanora tartarea}), from which the
powder is obtained.