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combining weight

(Encyclopedia)combining weight, the proportion (by weight) in which a chemical element combines with other elements to form compounds. The determination of combining weights was a very important part of early chemi...

atomic weight

(Encyclopedia)atomic weight, mean (weighted average) of the masses of all the naturally occurring isotopes of a chemical element, as contrasted with atomic mass, which is the mass of any individual isotope. Althoug...

Prout, William

(Encyclopedia)Prout, William, 1785–1850, English chemist and physician. Prout's hypothesis, advanced in 1815–16, suggested that atomic weights of elements are multiples of that of hydrogen and that elements are...

International System of Units

(Encyclopedia)International System of Units, officially called the Système International d'Unités, or SI, system of units adopted by the 11th General Conference on Weights and Measures (1960). It is based on the ...

Richards, Theodore William

(Encyclopedia)Richards, Theodore William, 1868–1928, American chemist, b. Germantown, Pa., Ph.D. Harvard, 1888. Richards was a professor at Harvard from 1891 until his death in 1928. In 1914 he received the Nobel...

Lavoisier, Antoine Laurent

(Encyclopedia)Lavoisier, Antoine Laurent äNtwänˈ lōräNˈ lävwäzyāˈ [key], 1743–94, French chemist and physicist, a founder of modern chemistry. He studied under eminent men of his day, won early recognit...

law of simple multiple proportions

(Encyclopedia)law of simple multiple proportions, in chemistry, the statement that when two or more elements form more than one compound, the ratio of the weights of one element that combine with a given weight of ...

Lagrange, Joseph Louis, Comte

(Encyclopedia)Lagrange, Joseph Louis, Comte zhôzĕfˈ lwē kôNt lägräNzhˈ [key], 1736–1813, French mathematician and astronomer, b. Turin, of French and Italian descent. Before the age of 20 he was professor...

Lowndes, Rawlins

(Encyclopedia)Lowndes, Rawlins loundz [key], 1721–1800, president of South Carolina (1778–79), b. St. Kitts. In 1730 his family moved to Charleston, S.C., where Lowndes later became a noted lawyer. In the colon...

Cannizzaro, Stanislao

(Encyclopedia)Cannizzaro, Stanislao stänēsläˈō kän-nēt-tsäˈrō [key], 1826–1910, Italian chemist. From 1861 he was professor at Palermo and from 1871 at Rome, where he was also a member of the senate and...