Litmus

(noun.) a coloring material (obtained from lichens) that turns red in acid solutions and blue in alkaline solutions; used as a very rough acid-base indicator.

录入:普勒斯顿

• In his right hand he held a slip of litmus-paper. 阿瑟·柯南·道尔. 福尔摩斯回忆录.
• Bases always turn red litmus paper blue. 伯莎M.克拉克. 科学通论.
• Hence, in order to detect the presence of acid in a substance, one has merely to put some of the substance on blue litmus paper, and note whether or not the latter changes color. 伯莎M.克拉克. 科学通论.
• But the best test of an acid is by sight rather than by taste, because it has been found that an acid is able to discolor a plant substance called litmus. 伯莎M.克拉克. 科学通论.
• If now red litmus paper is tested in the same solution, its color also will remain unchanged; such a result indicates infallibly the absence of any basic quality. 伯莎M.克拉克. 科学通论.

手打:莉莲