Nomenclature

(no'měn-clu-tūr.) [From L. nomenclatura, a calling by name.) A systematic cla ification of words, which designate the divisions and dependencies of a science. (Chem.) The Chemical N. is due to Lavoisier, and is based on the principle that the name of a compound should, as far as po ible, expre its composition and properties. The names of many of the elementary bodies having been received from the alchemists are arbitrary, but those of newly discovered metals are made to terminate in ium; metalloids in on, as boron; gases in ine or gen, as chlorine and oxygen. The names of compounds are framed according to definite rules. The simplest combinations oftwo elements are termed binary compounds, and fall naturally into two divisions - bases and acids. Bases always end in ide, and are compounds of different proportions of a metal with a metalloid. The proportion of the metalloid is indicated by the addition of a Greek or Latin numerical particle; thus we have the prot oxide, sesquioxide, binozide, and ter oxide of various metals, indicating that these compounds contain one, one and a half, two, and three doses of oxygen to one of metal. When the metal is in exce , Greek prefixes are used; we have, for instance, the dinozide or tris oxide of a metal, showing that the metal is in a double or triple dose. Generally, the prefixes sub and per are used to indicate the exce of metal over metalloid, and vice vers a. The amount of oxygen contained in oxy-acids is indicated by the termination ic or ous, or the prefixes hypo, under, or hyper, above. The compounds of acids with bases are always indicated by the termination or prefix of the word giving the name of the acid. Acids ending in ous or ic form salts ending in ite and ate, the prefix being, of course, preserved. When the oxide with which the acid is united is a prot oxide or peroxide, the prefixes proto and per are added: for instance, the per nitrate and proto nitrate are the nitrates of the prot oxide and peroxide of the metal. When the dose of acid is greater or le than the base, the prefixes sub, sesqui, bi, are used; as the sub carbonate,bicarbonate, and sesquicarbonate of soda. In double salts, the name of the base only is repeated; as the tar rate of potash and soda. The prefix pyro signifies that the acid or salt has been obtained by heat; for instance, pyro gallic acid produced in this way from gallic acid. In organic chemistry, the N. is in many cases somewhat confused. This is not owing to any want of proper principle in the formation of new words, but rather to the differences of opinion existing among chemists as to the composition of the substances indicated. Organic radicals generally terminate in yl, and mostly contain carbon, hydrogen, and oxygen. Thus we have ethyl the radical of ether, which forms oxides and salts in the same manner as iron, lead, or any of the purely elementary bodies. The termination ol or ole is generally applied to neutral compounds of carbon and hydrogen, po e ed of neither basic nor acid properties, and are mostly liquid, such as benzol, pyrol, quin ol. The termination in is applied to other neutral substances, generally solids; such as paraffin, naphthalin, and albumin. Those ending in ine or ia are generally bodies allied to the alkalies in their properties. Many of those which end in anine resemble ammonia, and are considered substitution compounds of that body, in which one or more equivalents of hydrogen are replaced by an organic radical. If two or three equivalents are replaced, the prefix di or tri is added to the word; for instance, we have dimethylamine, and tri propylamine, the composition of which is plainly indicated by their names. When the hydrogen is replaced by different bodies, their names are prefixed. We have, for instance, ethyl methyl-amyl a mine, which consists of one equivalent of nitrogen united to one each of the organic radicals, ethyl, methyl, and amyl. Thus, although these names appear unintelligible to the superficial observer, they are as easily understood by the chemical student as any term including several nouns and adjectives would be to an ordinary individual. Nominative, (nom'in-a-tiv.) [From L. nom ino, I name. (Gram.) The first case of declinable nouns. The N. case is the subject of a proposition or affirmation; thus, in the sentence " the work is done," work is the nominative case of the noun. Non, (non.) [L., not.] A word used in the English language as a negative prefix only; as, in non-appearance, non-residence, non -juror, . [s. 649]