NAMES AND SYMBOLS OF ELEMENTS.
Any history of the chemical elements, distinctly points to the enormous
stride which chemical discovery has taken within the last hundred
years. The dawn of this period was marked by many most important
results: among these may be mentioned the detection of the elementary
gases, oxygen, hydrogen and nitrogen. The light which these great
events threw upon the future of the science enabled the chemists
of that early period to perceive that the number of new compound
substances then discovered, and likely soon to be discovered, called
for a multitude of new terms. In 1787 the eminent French chemist,
Lavoisier, in committee with Guyton de Morveau and others of their
chemical associates of the French Academy, suggested a system by
which a considerable number of chemical compounds, both then known
and thereafter to be discovered, might be provided with names at
once convenient and suggestive. This system, slightly modified and
considerably extended—to accommodate the yet more widely expanding
needs of the science—affords the basis of the chemical language of
to-day.
A Few Principles of Chemical Language.
It is proposed to explain here a few of the first principles of
chemical nomenclature and notation; that is, to present a few of
the rules by which significant and useful _names and symbols_
are provided. These will be found to meet the wants of hitherto
inaccurately known substances, and even of those formerly unknown.
_First; the names of elementary substances long known are retained._
Thus, gold and silver are metals that were known in the earliest
historical periods, if not in prehistoric times; their names,
therefore, still remain in use.
_Second: the discoverers of new elementary substances assign the
names._ In so doing, they usually invent a name that suggests some
_fact_ connected with the substance itself. Thus the name nitrogen is
derived from two Greek words (νίτρον, _nitron_, mineral alkali, and
γεννάω, _gennao_, I produce) carrying the suggestion that the gas is
one of the constituents of nitre. The name hydrogen is derived from two
Greek words (ὕδωρ, _hydor_, water, and γεννάω, _gennao_, I produce,)
indicating that wherever water exists, hydrogen is an essential
constituent of it. So the name chlorine is derived from a Greek word
(χλωρός, _chloros_, green,) which reminds the chemist of the fact that
chlorine gas possesses a greenish color. The substance oxygen, however,
was named in a different manner. Its name is derived from two Greek
words (ὀξύς, _oxys_, acid, and γεννάω, _gennao_, I produce,) signifying
a generator of acids. It appears then, that in this case the name is
based, not on an easily verified fact, but upon a _theory_, current
when oxygen was discovered, of the action of the substance in question.
In a certain sense a name thus formed may be considered ill-advised.
Thus in the case in hand it has turned out that while oxygen is a
constituent of a majority of known acids, it is not essentially an
acidifying substance: many acids are known that contain no oxygen at
all, and again there are a multitude of compounds containing oxygen
that are not acids in any proper sense.
_Third; newly discovered metals are usually given names which, while
they suggest some property of the substance, have in addition the
termination, um._ Thus the metal thallium derives its name from a Greek
word (θάλλος, _thallos_, a green twig,) which carries the suggestion
of the fact that thallium and its compounds when highly heated evolve
light of a delicate green color. Again caesium, a newly discovered
metal, has a name derived from a Latin word (_caesius_, blue,) which
refers to the fact that caesium and its compounds when highly heated
afford light of a blue color. The termination _um_ is used for metals,
after the analogy of the Latin language which usually has its names of
metals end in _um_. Indeed the chemist often makes use of the Latin
names of even those metals that have been long known by more familiar
ones. Thus for gold the Latin word _aurum_ is used, for silver the
Latin word _argentum_, for lead the Latin word _plumbum_; it will
be seen later that slightly modified forms of these names are very
frequently employed when compounds of these metals are to be designated.
[Illustration: ANTOINE LAURENT LAVOISIER:
Born in Paris, August 26th, 1743; died on the scaffold in Paris, May
8th, 1794.]
Symbols used for Atoms.
Each elementary substance, or, strictly speaking, the minute quantity
of it represented by the term one atom, may be designated in brief by a
special letter or short group of letters called the symbol. The usual
symbol is the initial letter of the native or the Latin name of the
substance. Upon examining the list of elementary substances at page 13,
it will be seen that the following nine of the names begin with the
letter _C_; of course, therefore, in eight cases at least, the symbol
must contain an additional distinguishing letter:
Accordingly C indicates one atom of Carbon;
Ca ” ” Calcium;
Cd ” ” Cadmium;
Ce ” ” Cerium;
Cl ” ” Chlorine;
Co ” ” Cobalt;
Cr ” ” Chromium;
Cs ” ” Caesium;
Cu ” ” Copper (Latin word _cuprum_).
It also appears that in the case of metals, like iron and copper, known
to the ancients the symbols used are derived from the Latin names. The
use of these symbols made from letters—and therefore called literal
symbols, from the Latin word _litera_, a letter—will become apparent
as the reader advances; but it is easily perceived that they afford a
convenient abridgement of the longer titles of the elements.
The use of literal symbols as an abridgement of the chemical
nomenclature was first proposed by Berzelius, a Swedish chemist, whose
eminence in every branch of the science was such that the suggestion
here referred to constitutes one of the least of the many and
substantial grounds on which his fame rests.
READING REFERENCES.
Alchemy.
=Rodwell=, G. F.—The Birth of Chemistry. London. 1874.
=Draper=, J. C.—Amer. Chemist, v, 1.
=Mackay=, Charles.—Memoirs of Extraordinary Popular Delusions.
2 v. London. 1869. i, 93.
Berzelius.
=Wöhler=, F.—Early Recollections of Berzelius.
Am. Chemist, vi, 131.
Chemistry, History of
=Thomson=, Thomas.—History of Chemistry, 2 v. London. 1830.
=Hoefer=, F.—Histoire de la Physique et de la Chimie. Paris.
1872.
=Kopp=, Hermann.—Geschichte der Chemie. 4Th. Braunschweig.
1843.
———— Die Entwickelung der Chemie in der neueren Zeit. München.
1873.
=Bolton=, H. C.—Chem. News. xxxii, 36, 56, 68.
=Liebig=, J. v.—Familiar Letters on Chemistry.
=Whewell=, Wm.—History of the Inductive Sciences. 2 v.
New York. 1875. ii, 259.
[Illustration: JONS JAKOB BERZELIUS:
Born in East Gothland (in Sweden), Aug. 20, 1799; died Aug. 7, 1848.]
Lavoisier,
=Thomson=, Thomas,—History of Chemistry. 2 v.
London. 1830. ii, 75.
=Figuier=, L.—Vies des Savants Illustres du xviii siècle,
444.
=Brougham=, H.—Lives of Philosophers of the time of
George III. Edinburgh, 1872. 290.
Nomenclature.
=Morveau=, Guyton de.—Memoire sur les denominations chimiques,
la necessité d’en perfectionner le système, les règles pour y
parvenir, suivi d’un tableau d’une nomenclature chimique; Dijon.
1782.
=Lavoisier=, de Morveau, Fourcroy, Baumé, Hassenfratz, Adet
and others. Méthode de nomenclature chimique. Paris. 1787.
(The Boston Athenæum Library contains a copy of this work.)