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locust, in botany

(Encyclopedia)locust, in botany, any species of the genus Robinia, deciduous trees or shrubs of the family Leguminosae (pulse family) native to the United States and Mexico. The locusts have pendent clusters of flo...

geode

(Encyclopedia)geode jēˈōd [key], hollow, globular rock nodule ranging in diameter from 1 to 12 in. (2.54–30.5 cm) or more. Most geodes are partly filled with mineral matter; they have a thin layer of chalcedon...

menthol

(Encyclopedia)menthol, white crystalline substance with a characteristic pungent odor. It is derived from the oil of the peppermint plant, Mentha piperita (see mint), or prepared synthetically from coal tar. An alc...

Heck, Richard Fred

(Encyclopedia)Heck, Richard Fred, 1931–2015, American chemist, b. Springfield, Mass., Ph.D. Univ. of California, Los Angeles, 1954. Heck was a researcher at the Hercules Corporation in Wilmington, Del., from 1957...

silicone

(Encyclopedia)silicone, polymer in which atoms of silicon and oxygen alternate in a chain; various organic radicals, such as the methyl group, CH3, are bound to the silicon atoms. Silicones, which are unusually sta...

dye

(Encyclopedia)dye, any substance, natural or synthetic, used to color various materials, especially textiles, leather, and food. Natural dyes are so called because they are obtained from plants (e.g., alizarin, cat...

Wöhler, Friedrich

(Encyclopedia)Wöhler, Friedrich frēˈdrĭkh vöˈlər [key], 1800–1882, German chemist. He studied under the German chemist Leopold Gmelin and J. J. Berzelius, a Swedish chemist, and in 1836 was appointed profe...

Berthelot, Pierre Eugène Marcelin

(Encyclopedia)Berthelot, Pierre Eugène Marcelin pyĕr ûzhĕnˈ märsəlăNˈ bĕrtəlōˈ [key], 1827–1907, French chemist. He was professor at the École Supérieure de Pharmacie (1859) and at the Collège de ...

ethyl

(Encyclopedia)ethyl ĕthˈəl [key], CH3CH2, organic free radical or alkyl group derived from ethane by removing one hydrogen atom. ...

mechanism

(Encyclopedia)mechanism, philosophical theory about the nature of organic systems, holding that organisms are machines in the sense that they are material systems. Mechanism seeks to explain biological processes, i...