| 释义 |
ulmic, a. Chem.|ˈʌlmɪk|
[f. L. ulm-us elm, after ulmin. Cf. F. ulmique, Pg. ulmico.]
ulmic acid: a. = ulmin 1.
A distinction between ulmic acid and ulmin or ulmine has been made by various chemists, but without agreement in the precise application of the terms.
1831T. Thomson Chem. Inorg. Bodies II. 105 Ulmic acid appears to be a vegetable substance of very great importance..obtained from the exudation of the elm by dissolving the exudation in water and precipitating the ulmic acid. 1836Brande Man. Chem. 923 As it [sc. ulmin] combines with bases, Boullay terms it ulmic acid... He represents ulmin, or ulmic acid, as a compound [etc.]. 1868Watts Dict. Chem. V. 936 The name ‘ulmic acid’, or ‘ulmin’, was given by Klaproth to a gummy substance contained in the black alkaline excrescences on the stems of unhealthy trees, especially of elms.
b. = ulmin 2.
1843Penny Cycl. XXV. 491/1 Ulmic acid plays an important part in manures and soils, and what is called moss⁓water owes its peculiar properties to its presence. 1868Watts Dict. Chem. V. 936 The ammoniacal solution..deposits brown or black gelatinous flocks of ulmic acid. |