nomenclature

[Latin nomenclatura =a calling by name.] [NOMENCLATOR.] *I. Ordinary Language : 1. A name, a title, a designation. "There wanteth a term or nomenclature for it."-Bacon: Natural History. 2. A vocabulary, a dictionary, a glo ary. II. Science: The names taken collectively of the objects of study in any branch of science. Sometimes it includes, but far more generally it is distinguished from, terminology. In botany, for example. the names a igned to the several cla es, orders, tribes, genera, species, ., are its nomenclature; the definition of the various words, whether substantives or adjectives, used in describing a plant, belong to terminology. The designation, Rosa can in a (Dog-rose), falls under the department of nomenclature; nectary, diœcio us, ., under that of terminology. In 1842 the subject of scientific nomenclature was investigated and reported on by a Committee of the British A ociation. 1. Biol .: The practice of using two names-one generic, the other specific; it originated with Linnæus. [2,6.] 2. Bot .: Linnæus laid down thirty-one rules for guidance of botanists in nomenclature; some of these have fallen into di e Orders gener ally end in -aceæ, tribes in ee, and their subdivisions in -ide. Botanical a emblages with the last-named ending are called, in this work, families; though family in botany is sometimes made synonymous with order. This brings them into harmony with zoological families in ide, to which they are apparently equivalent. 3. Chem.: The spoken language of chemistry, which at every period of its history reflects the stage of its development. The early belief that the heavenly bodies determined the character of terres trial matter led to the use of such names as sol= gold, luna silver, and mercury, the name by which the metal is still known. Later, the physical char- acter of the substance gave rise to the name of the compound, as in milk of lime, sugar of lead. But the present system is, with some minor variations, the work of Lavoisier, Berthollet, and Morveau, and appeared in 1787. The leading principle is that the names of compound bodies should expre the simple substances they contain, and their relative proportions. Generally the root-word is employed, together with certain terminations and prefixes to indicate the degree of oxidation and the number of atoms of the elements contained in it-e. g., KNO3 =pota ic nitrate, KNO2=pota ic nitrite, HNO3= nitric acid, HNO2=nitrous acid. The following compound shows the manner in which the numeral HgCl2 prefixes are employed: H02 02 = tetra-mercuro- (N2