10. (Mus.)
(a) Produced by natural organs, as those of the human
throat, in distinction from instrumental music.
(b) Of or pertaining to a key which has neither a flat
nor a sharp for its signature, as the key of C major.
(c) Applied to an air or modulation of harmony which
moves by easy and smooth transitions, digressing but
little from the original key. --Moore (Encyc. of
Music).
{Natural day}, the space of twenty-four hours. --Chaucer.
{Natural fats}, {Natural gas}, etc. See under {Fat}, {Gas}.
etc.
{Natural Harmony} (Mus.), the harmony of the triad or common
chord.
{Natural history}, in its broadest sense, a history or
description of nature as a whole, incuding the sciences of
{botany}, {zo["o]logy}, {geology}, {mineralogy},
{paleontology}, {chemistry}, and {physics}. In recent
usage the term is often restricted to the sciences of
botany and zo["o]logy collectively, and sometimes to the
science of zoology alone.
{Natural law}, that instinctive sense of justice and of right
and wrong, which is native in mankind, as distinguished
from specifically revealed divine law, and formulated
human law.
{Natural modulation} (Mus.), transition from one key to its
relative keys.
{Natural order}. (Nat. Hist.) See under {order}.
{Natural person}. (Law) See under {person}, n.
{Natural philosophy}, originally, the study of nature in
general; in modern usage, that branch of physical science,
commonly called {physics}, which treats of the phenomena
and laws of matter and considers those effects only which
are unaccompanied by any change of a chemical nature; --
contrasted with mental and moral philosophy.
{Natural scale} (Mus.), a scale which is written without
flats or sharps. Model would be a preferable term, as less
likely to mislead, the so-called artificial scales (scales
represented by the use of flats and sharps) being equally
natural with the so-called natural scale
{Natural science}, natural history, in its broadest sense; --
used especially in contradistinction to mental or moral
science.
{Natural selection} (Biol.), a supposed operation of natural
laws analogous, in its operation and results, to designed
selection in breeding plants and animals, and resulting in
the survival of the fittest. The theory of natural
selection supposes that this has been brought about mainly
by gradual changes of environment which have led to
corresponding changes of structure, and that those forms
which have become so modified as to be best adapted to the
changed environment have tended to survive and leave
similarly adapted descendants, while those less perfectly
adapted have tended to die out though lack of fitness for
the environment, thus resulting in the survival of the
fittest. See {Darwinism}.
{Natural system} (Bot. & Zo["o]l.), a classification based
upon real affinities, as shown in the structure of all
parts of the organisms, and by their embryology.
It should be borne in mind that the natural system
of botany is natural only in the constitution of its
genera, tribes, orders, etc., and in its grand
divisions. --Gray.
{Natural theology}, or {Natural religion}, that part of
theological science which treats of those evidences of the
existence and attributes of the Supreme Being which are
exhibited in nature; -- distinguished from revealed
religion. See Quotation under {Natural}, a., 3.
{Natural vowel}, the vowel sound heard in urn, furl, sir,
her, etc.; -- so called as being uttered in the easiest
open position of the mouth organs. See {Neutral vowel},
under {Neutral} and Guide to Pronunciation, [sect] 17.
2. A book which treats of the science of botany.
Note: Botany is divided into various departments; as,
{Structural Botany}, which investigates the structure and
organic composition of plants;
{Physiological Botany}, the study of their functions and
life; and
{Systematic Botany}, which has to do with their
classification, description, nomenclature, etc.