Two propylene glycols, C3H8O2, are known, viz. [alpha]-propylene
glycol, CH3.CH(OH).CH2OH, a liquid boiling at 188 deg. to 189 deg.,
and obtained by heating glycerin with sodium hydroxide and distilling
the mixture; and trimethylene glycol, CH2OH.CH2.CH2OH, a liquid
boiling at 214 deg. C. and prepared by boiling trimethylene bromide
with potash solution (A. Zander, _Ann._, 1882, 214, p. 178).
GLYCONIC (from Glycon, a Greek lyric poet), a form of verse, best known
in Catullus and Horace (usually in the catalectic variety _ [u_] _ u u _
u [u_]), with three feet--a spondee and two dactyls; or four--three
trochees and a dactyl, or a dactyl and three chorees. Sir R. Jebb
pointed out that the last form might be varied by placing the dactyl
second or third, and according to its place this verse was called a
First, Second or Third Glyconic.
Cf. J. W. White, in _Classical Quarterly_ (Oct. 1909).
GLYPH (from Gr. [Greek: glyphein], to carve), in architecture, a
vertical channel in a frieze (see TRIGLYPH).
GLYPTODON (Greek for "fluted-tooth"), a name applied by Sir R. Owen to
the typical representative of a group of gigantic, armadillo-like, South
American, extinct Edentata, characterized by having the carapace
composed of a solid piece (formed by the union of a multitude of bony
dermal plates) without any movable rings. The facial portion of the
skull is very short; a long process of the maxillary bone descends from
the anterior part of the zygomatic arch; and the ascending ramus of the
mandible is remarkably high. The teeth, 8/8 in the later species, are
much alike, having two deep grooves or flutings on each side, so as to
divide them into three distinct lobes (fig.). They are very tall and
grew throughout life. The vertebral column is almost entirely welded
into a solid tube, but there is a complex joint at the base of the neck,
to allow the head being retracted within the carapace. The limbs are
very strong, and the feet short and broad, resembling externally those
of an elephant or tortoise.
[Illustration: Two views of the tooth of a _Glyptodon_; the upper figure
showing one side, and the lower the crown.]
Glyptodonts constitute a family, the _Glyptodontidae_, whose position
is next to the armadillos (_Dasypodidae_); the group being represented
by a number of generic types. The Pleistocene forms, whose remains
occur abundantly in the silt of the Buenos Aires pampas, are by far
the largest, the skull and tail-sheath in some instances having a
length of from 12 to 16 ft. In _Glyptodon_ (with which
_Schistopleurum_ is identical) the tail-sheath consists of a series of
coronet-like rings, gradually diminishing in diameter from base to
tip. _Daedicurus_, in which the tail-sheath is in the form of a huge
solid club, is the largest member of the family, in _Panochthus_ and
_Sclerocalyptus_ (_Hoplophorus_) the tail-sheath consists basally of a
small number of smooth rings, and terminally of a tube. In some
specimens of these genera the horny shields covering the bony scutes
of the carapace have been preserved, and since the foramina, which
often pierce the latter, stop short of the former, it is evident that
these were for the passage of blood-vessels and not receptacles for
bristles. In the early Pleistocene epoch, when South America became
connected with North America, some of the glyptodonts found their way
into the latter continent. Among these northern forms some from Texas
and Florida have been referred to _Glyptodon_. One large species from
Texas has, however, been made the type of a separate genus, under the
name of _Glyptotherium texanum_. In some respects it shows affinity
with _Panochthus_, although in the simple structure of the tail-sheath
it recalls the undermentioned _Propalaeohoplophorus_. All the above
are of Pleistocene and perhaps Pliocene age, but in the Santa Cruz
beds of Patagonia there occur the two curious genera
_Propalaeohoplophorus_ and _Peltephilus_, the former of which is a
primitive and generalized type of glyptodont, while the latter seems
to come nearer to the armadillos. Both are represented by species of
comparatively small size. In _Propalaeohoplophorus_ the scutes of the
carapace, which are less deeply sculptured than in the larger
glyptodonts, are arranged in distinct transverse rows, in three of
which they partially overlap near the border of the carapace after the
fashion of the armadillos. The skull and limb-bones exhibit several
features met with in the latter, and the vertebrae of the back are not
welded into a continuous tube. There are eight pairs of teeth, the
first four of which are simpler than the rest, and may perhaps
therefore be regarded as premolars. More remarkable is _Peltephilus_,
on account of the fact that the teeth, which are simple, with a
chevron-shaped section, form a continuous series from the front of the
jaw backwards, the number of pairs being seven. Accordingly, a
modification of the character, even of the true Edentata, as given in
the earlier article, is rendered necessary. The head bears a pair of
horn-like scutes, and the scutes of the carapace and tail, which are
loosely opposed or slightly overlapping, form a number of transverse
rows.
LITERATURE.--R. Lydekker, "The Extinct Edentates of Argentina," _An.
Mus. La Plata_--_Pal. Argent._ vol. iii. p. 2 (1904); H. F. Osborn,
"'Glyptotherium texanum,' a Glyptodont from the Lower Pleistocene of
Texas," _Bull. Amer. Mus._, vol. xvii. p. 491 (1903); W. B. Scott,
"Mammalia of the Santa Cruz Beds--Edentata," _Rep. Princeton Exped. to
Patagonia_, vol. v. (1903-1904). (R. L.*)
GLYPTOTHEK (from Gr. [Greek: glyptos], carved, and [Greek: theke], a
place of storage), an architectural term given to a gallery for the
exhibition of sculpture, and first employed at Munich, where it was
built to exhibit the sculptures from the temple of Aegina.
GMELIN, the name of several distinguished German scientists, of a
Tubingen family. Johann Georg Gmelin (1674-1728), an apothecary in
Tubingen, and an accomplished chemist for the times in which he lived,
had three sons. The first, Johann Conrad (1702-1759), was an apothecary
and surgeon in Tubingen. The second, Johann Georg (1709-1755), was
appointed professor of chemistry and natural history in St Petersburg in
1731, and from 1733 to 1743 was engaged in travelling through Siberia.
The fruits of his journey were _Flora Sibirica_ (4 vols., 1749-1750) and
_Reisen durch Sibirien_ (4 vols., 1753). He ended his days as professor
of medicine at Tubingen, a post to which he was appointed in 1749. The
third son, Philipp Friedrich (1721-1768), was extraordinary professor of
medicine at Tubingen in 1750, and in 1755 became ordinary professor of
botany and chemistry. In the second generation Samuel Gottlieb
(1743-1774), the son of Johann Conrad, was appointed professor of
natural history at St Petersburg in 1766, and in the following year
started on a journey through south Russia and the regions round the
Caspian Sea. On his way back he was captured by Usmey Khan, of the
Kaitak tribe, and died from the ill-treatment he suffered, on the 27th
of July 1774. One of his nephews, Ferdinand Gottlob von Gmelin
(1782-1848), became professor of medicine and natural history at
Tubingen in 1805, and another, Christian Gottlob (1792-1860), who in
1828 was one of the first to devise a process for the artificial
manufacture of ultramarine, was professor of chemistry and pharmacy in
the same university. In the youngest branch of the family, Philipp
Friedrich had a son, Johann Friedrich (1748-1804), who was appointed
professor of medicine in Tubingen in 1772, and in 1775 accepted the
chair of medicine and chemistry at Gottingen. In 1788 he published the
13th edition of Linnaeus' _Systema Naturae_ with many additions and
alterations. His son Leopold (1788-1853), was the best-known member of
the family. He studied medicine and chemistry at Gottingen, Tubingen and
Vienna, and in 1813 began to lecture on chemistry at Heidelberg, where
in 1814 he was appointed extraordinary, and in 1817 ordinary, professor
of chemistry and medicine. He was the discoverer of potassium
ferricyanide (1822), and wrote the _Handbuch der Chemie_ (1st ed.
1817-1819, 4th ed. 1843-1855), an important work in its day, which was
translated into English for the Cavendish Society by H. Watts
(1815-1884) in 1848-1859. He resigned his chair in 1852, and died on the
13th of April in the following year at Heidelberg.
GMUND, a town of Germany, in the kingdom of Wurttemberg,[1] in a
charming and fruitful valley on the Rems, here spanned by a beautiful
bridge, 31 m. E.N.E. of Stuttgart on the railway to Nordlingen. Pop.
(1905) 18,699. It is surrounded by old walls, flanked with towers, and
has a considerable number of ancient buildings, among which are the fine
church of the Holy Cross; St John's church, which dates from the time of
the Hohenstaufen; and, situated on a height near the town, partly hewn
out of the rock, the pilgrimage church of the Saviour. Among the modern
buildings are the gymnasium, the drawing and trade schools, the Roman
Catholic seminary, the town hall and the industrial art museum. Clocks
and watches are manufactured here and also other articles of silver,
while the town has a considerable trade in corn, hops and fruit. The
scenery in the neighbourhood is very beautiful, near the town being the
district called Little Switzerland.
Gmund was surrounded by walls in the beginning of the 12th century by
Duke Frederick of Swabia. It received town rights from Frederick
Barbarossa, and after the extinction of the Hohenstaufen became a free
imperial town. It retained its independence till 1803, when it came into
the possession of Wurttemberg. Gmund is the birth-place of the painter
Hans Baldung (1475-1545) and of the architect Heinrich Arler or Parler
(fl. 1350). In the middle ages the population was about 10,000.
See Kaiser, _Gmund und seine Umgebung_ (1888).