library j;ivfs much bibliograpliie iul'ormation by mail and tbrough its publications, which, includ- ing its annual reports and reference lists, are distributed freely to institutions and serious in- vestigators. It issues no general catalogue in book form. Its printed catalogue cards are, how- ever, placed for reference at certain centres of re- search outside of Washington, and are supplied at cost to subscribing libraries. It is thus be- coming a central bureau for the cataloguing of all current copyrighted publications and of most others, current and non-current, that are of con- cern to American libraries.
The organization, history, and operations of the library are described in various of its publi- cations, particularly the Librarian's Report for lOfll. The building is most fully described in Small. Handbook of the Library of Congress (Boston. 1901).
LIBRATION (Lat. Ilbratio. a balancing,
from Vibriire. to poise, from libra, balance). A
term applied to certain phenomena of the moon's
motion. The moon's librations (or, more prop-
erly, apparent librations) are of three kinds —
libration in longitude, libration iti latitude, and
the diurnal libration. If the moon's rotation in
tlie orbit were uniform, as her rotation on the
axis is. we should always see exactly the same
portion of her surface: but as this is not the case,
there are two small strip.s of surface running
from pole to pole, on the east and west sides,
which become alternately visible; this is called
the moon's longitudinal libration. The libration
in latitude arises from the moon's axis not being
perpendicular to her orbit, in consequence of
which a portion of her surface round the north
jiole is visible during one-half, and a correspond-
ing portion round the south pole during the other
half of her revolution in her orbit. The diurnal
libration hardly deserves the name, and is simply
a consequence of the observer's position on the
surface of the earth, and not at the centre; it
consists in the gradual disappearance of certain
points on one edge of the moon's disk as she
approaches her culmination, and the appearance
of new points on her opposite border as she de-
scends. The combined efl'ect of all three libra-
tions is that we can see altogether 59 per cent,
of the moon's surface; whereas without the libra-
tions we should see only .tO per cent., or one-
lialf. Tlie first and tliird of these librations were
discovered by Galileo, and the second by Hevelius.
LIBRETTO,' le-bret'tS (It., little book) . The
book or text of any extended vocal composition,
notably an oratorio or o])era. As the Italian
opera degenerated the libretto became more and
more trivial. During the latter half of the eigh-
teenth and the first half of the nineteenth century
the text was of so little importance that the
sauK libretto would be retouched or slightly
altered and set to music by many different com-
posers. Serious composers always had difficulty
Avith librettists. Beethoven for a long time wished
to write operas, but after his experience with
Fidclio abandoned dramatic composition forever,
because he could not find a suitable text. Wag-
ner began his reforms by insisting upon a good
text. But. being a poet himself, he was not de-
]K'iidfnt upon others. The texts of his earlier
works (to Lohenqrin inclusive) are libretti in the
true sense, being divided into arias, choruses,
duets, quartets, etc. But they possess literary
merit because of the logical and artistic develop-
ment ol the plot and the beauty and force of the
language. It would be wrong to apply the term
libretto to the text of Wagner's later works.
They are dranuis iu the true sense of the word.
The inlluence exerted by Wagner upon librettists
has been so strong that, as a rule, modern serious
libretti possess some literary merit.
LIBREVILLE, lebr'-vel'. The capital of
I'rench Congo. West Africa, situated on the coast
at the estuary of the Gabun (.Map; Africa, E 4).
It is an important seaport and coaling-station.
The population consists of about 5000 natives and
over 2tl0 Europeans.
LIBRI-CARRirCCI, le'br* ka-roii'ch*, Gu-
GLiELMo, Count (1803-69). A French mathe-
matician. He was born at Florence, and was
educated at Pisa, where he was professor of
matlienuitics until 1830, when he went to Paris
as a political refugee. He was naturalized in
1833; became professor of analysis at the Sor-
bonne ; and succeeded Legendre in the Academy
of Sciences. He was promoted to be inspector-
general of the University and of the public li-
braries of Paris. In 1848 he was accused of
stealing valuable books and manuscripts under
his charge; in 1850, after his escape to England,
he was found guilty, and was sentenced to ten
years' imprisonment. Among his really impor-
tant works in mathematics and physics are con-
tributions to Crelle's Journal (1835). and the
Histoire des sciences mathematiques (1838-41
and ISfio).
LIBRO D'ORO, le'bro do'rd (It., Golden Book). A book in which w-as inscribed, origi- nally in letters of gold, a roll of all members of the nobility of Venice. All persons twenty-five years of age whose names were there registered were members of the Grand Council. The Golden Book of Venice was burned by Napoleon in 1797. Similar registers were kept in other Italian re- publics, and the term came to mean in general any list of honors.
LIBUR'NIA ( Lat.. from Gk. AtySoi/pvCa, Libour- nia). In ancient geography, a mountainou.'i district of lllyricum, on the Adriatic coast, now a part of Croatia and Dalmatia. From early times the Liburni were daring seamen, and were in the possession of Corcyra. Issa. and other isl- ands when the Greeks occupied these places. They were noted pirates, and tlieir privateers, with large lateen sails, were for centuries the terror of the seas. The galleys of the Liburni were noted for their light construction and swiftness, and the Romans, adopting this style of naval architecture, called all fast-sailing vessels naves Liburntr. By means of these light galleys .ugustus gained the battle of Actium. The only important towns in Liburnia were lader and Scardona.
LIBYA, lihl-a (Lat.. from Gk. .V./SiJt;, Libxii). The name given by the oldest geographers to the whole continent of Africa. In the Roman jx-riod the name Africa was generally used for the con- tinent as a whole, while the name Libya was ap- plied specifically to what is now known as the Libyan Desert, together with the strip of land just north thereof, lying along the coast. Se« Afrtca.
LIBYAN, lib'ynn {LuJxi, Leraia. Egypt. Lebu. Gk. Alpves, Libiies) . A branch of the Hamitic stock, or linguistic family, occupying from most ancient times the north of Africa between the Barcan Desert and the Atlantic Ocean.
