Physics - Mechanics
Physics
Few sectors that currently
belong to the science of physics were cultured from the scholars of Late
Antiquity and Byzantium. The autonomy of sciences is, after all, a phenomenon
that is rarely found before the Age of Enlightenment. Most of the sections that
are now covered by physics were integrated in the sciences of Mathematics or
Engineering during the Late Antiquity.
Typical cases of scientists who dealt
with physics are the two "engineers"
of Αgia Sophia, Anthemius of Tralles and
Isidore of Miletus. Anthemius, who came from a family of scholars, was educated
under the philosopher, astronomer and orator Ammonius in Alexandria. His
contemporaries, Procopius, Agathias Scholasticus and Paul Silentiarius praised
performance in mathematics and engineering. It is referred that he made
references on the works of earlier mathematicians like Nicomachus of Gerasa,
and developed the theory of deficiencies based on Archimedes and Apollonius. In
his work On the Parabola he analyzed
the structure of the parable, while significant is regarded his contribution to
the development of the theory of conic sections. In the
treatise On Wondrous Machines he develops his theory of concave mirrors, and
specifically about how solar
rays can be concentrated in one spot with the aid of a concave mirror,
regardless of season and time. Agathias mentions an incident
from the life of Anthemius in Constantinople, which reveals his ingenuity and
skills in applying the hydraulics. Specifically, his neighbour, Zeno the orator, added an upper floor
to his house, thus blocking off the light to Anthemius’ one storey home. To get
his revenge Antemius built a boiler and pipe mechanism which, when heated to
boiling point, produced an artificial steam-induced earthquake, an explosion
and damage
to the neighbour's extension. On the other hand,
Isidore of Miletus was just as good mathematician: he saw to the publication of Aristotle’s works, while a student of
his, perhaps the engineer and astronomer Leontes, rescued
the fifteenth book of Euclid’s Elements.
Also, Isidore annotated the (now lost) work of Heron Kamarika, demonstrating his interest as an engineer for the
construction of domes. Therefore, the church of Agia Sophia was a daring
project, which also had the sense of an experiment, although in Late Antiquity
and the later Byzantine period the concept of experiment and experimental
knowledge was completely unknown.
In
the middle and late Byzantium Physics was treated as a supplement to the study
of mathematics and of naturalist courses of quadrivium. In the work of Michael
Psellos entitled Teaching Pantodapi
some questions and answers refer to issues of heat and thermodynamics, while on
questions of interpretation of natural or meteorological phenomena, the
treatise is based on works of ancient philosophers like Plato and Aristotle,
and the Neo-Platonic. In the manual of Nikiforos Blemmydes, On physics, which was written for the
students of the school he had founded in the monastery of God near Ephesus in
the years around 1260, the content and structure of Aristotelian physics
(Physics, On genesis and decay, on sky, weather) was followed, but the essay
was based on earlier works, particularly of the neo-Platonics.
Mechanics
During the period of Late Antiquity, those who were
engaged in solving mechanical problems were generally themselves toolmakers,
slaves or manual laborers. Given this, we can understand the reasons for which
few were those who dealt with the development of technique, while even fewer
were those writing books for their achievements. Also, the machines built, never
surpassed the experimental stage, there weren’t any suggestions for their improvement,
as there was no scientific debate, while mass production was inconceivable. So since
the engineers were few, the mechanicals were even fewer and the financiers of
mechanical surveys very few, there has not been any substantial progress in the
field of technology.
One exception was Pappus
from Alexandria, whose work Synagoge gathered
together the ancient knowledge of engineering. In the work in question he
listed all the renowned devices of the past, thus far considered, to one degree
or another, landmarks in the history of engineering: levers, catapults, water
hoisting machinery, "automatons", solar and hydraulic clocks and globes
with celestial bodies that were activated by hydraulics.
Particularly in the case of automatons, anyone
interested in devices operated by hydraulic fluid systems (water or air)
consulted the work of Hero of Alexandria.
The engineers of Late Antiquity and Byzantium
not only preserved the old knowledge, but also developed it as far as they
could, under the given circumstances. Indeed, the encomiastic description
(expression) by the orator Procopius of the three-story
clock dominating the market of Gaza, describes its decoration, leaving
us to comprehend the complex inner mechanism dating to the early years of the
6th century: trumpets and knocks of the statue
of Perseus to Medusa’s head stroked the hours; then, the statue of Helios on his chariot pointed with his finger at
one of twelve doors in the upper floor, which opened to reveal a sculpture
ensemble depicting one of the twelve labours of Hercules; finally, at
the base of the clock, Pan and satyrs with nymphs were depicted. Also, the astronomer and engineer Leontes, in
his work On the construction of the Aratius
Sphere gives instructions for the construction of the sphere of the earth
and for the engraving on it lines of the equator, the tropical and the course
of the twelve zodiac signs, according to the glorification of the
constellations in the known poem of the great poet of the Hellenistic period
Aratus from Soli, Phenomena and Diosimeia, even correcting some of his mistakes.
Finally, according to the descriptions by both
Emperor Constantine Porphyrogenitus and Liutprand, later Bishop of Cremona, the
royal throne in the palace of Magnaura rose up to the top of the formal hall, while
foreign visitors worshiping with the face glued to the floor while at the same time instruments played music,
metal lions opened their mouths and roared, and birds sang on silver trees
above the throne. All these marvels were nothing more than applications
of the principles that Heron first Heron had described. The first two projects
reveal that up until the 7th century knowledge
of engineering was possessed by scholars in the capital and the provinces, and
they passed on major mechanical accomplishments of their own time or earlier to
the wider public, like the mechanical glove and the clock of Gaza. The mechanical lifting of the emperor’s
throne or the operation of a copper device with pipes carrying hot water and transmitting
heat like the current radiators, in the bath built by Dighenis Akritas,
according to the well-known self-titled epic, testified that the engineers from
the 9th century onwards worked exclusively for
the emperor and the palace.
Byzantine geometers knew how to use a
surveying instrument called the dioptra. A seventh or eighth century
topographer known to us as Hero(some identify him as Hero the Younger) co-wrote
a book on how to solve practical problems involved in calculating distances
between points and surfaces using the instrument in question, which is
considered the precursor of today's theodolite. The astrolabe, which was the
chief instrument of astronomy, used to calculate the azimuth and determine the
distances between celestial bodies, intrigued
important scholars such as John Philoponus,
Nikiforos Grigoras and Isaac Argyros, who wrote relevant titled treatises. (The only surviving Byzantine astrolabe, with an
inscription dating it to 1062, is held in the Museum of Brescia). Finally,
the numerous medical instruments, most of which are mentioned by Oribasius, the
portable solar watches, the weights and measures, and the utensils mentioned by
the alchemists are all included in the tools’ technology.
Glossary (0)
Information Texts (3)
The church of Agia Sophia:
Agia Sophia, which now serves as a museum, lies on the north-eastern
side of Sultan
Αhmet Square, opposite the Blue Mosque. The present day
church is the third built on the same site: the original Agia Sophia, founded
by Constantine the Great, was destroyed by fire in 404, when riots broke out in
Constantinople over the dethronement of
Patriarch John Chrysostom; the church renovated by Emperor Theodosius II
suffered irreparable damage in 532, also by fire during the Nika Revolt.
Agia Sophia (Holy Wisdom) and Agia Irene (Holy Peace) were dedicated to
attributes of God, and together served as the churches of the Patriarchate.
However, only Agia Sophia went down in history as the "Great Church".Construction work began immediately after Emperor Justinian had
suppressed the Nika revolt, and was assigned to engineers Anthemius of Tralles
and Isidore of Miletus. The building was completed in five years and eleven
months, and was inaugurated in December 537. Agia Sophia is considered one of
the most splendid buildings of its time – even if this church was the only
surviving Byzantine building, it would still be worth our while to study and
admire Byzantine culture. In his work On
Buildings, the historian Procopius describes the splendour and magnificence
of the church, which stunned the faithful on account of its size and beauty, and
the variety and richness of its decoration. The book also gives an account of
the construction process and recounts the technical problems faced by the
architects in erecting such a large building. As he writes, these were
corrected thanks to the genius of Justinian, who gave the architects
wise advice. Agia Sophia had to be larger, more majestic and more sumptuously decorated
than the church
of Agios Polyeuctus
founded a few years earlier by the affluent Anicia Juliana,
who hoped to put her son Olybrius on the throne.Agia Sophia is a combination of a domed basilica and a centrally
planned building. Its construction was revolutionary and innovative for its
time: the ground plan of the church forms a rectangle 77 by 71 metres, ending
in and apse to the east and in a narthex and an exonarthex
to the west. Inside, four large pillars stand in the corners of the nave,
forming a 31 metre sided square. The pillars are connected to four
arches, of which the north and south are very shallow, while the east and west end
in four large conches to the east and west of the central square. The dome
rests on forty ribs flanking forty windows in the lower section, pouring light
into the central nave. The side aisles have galleries, of which the
south was used by the emperor, his family, his senior officials and palace
courtiers to attend the liturgy. Access to the nave is gained via five doors in
the narthex, the middle one being known as the Royal Door.The church is famous not only for its architecture, but also for the mystical
atmosphere created by light as it bounces off the precious materials glittering
in the interior. The windows around the dome diffuse light and lend an
impression of weightlessness and evanescence, creating the illusion that the vaults
are floating and the dome is hanging from the sky. On the inside, the opulence
and luxury of the materials used is awe-inspiring. According to Procopius,
columns, marble, works of art and precious materials were brought from all the
provinces of the empire to realize Justinian’s vision. The walls and
pillars of the nave are dressed with green and dark blue-grey marble revetments,
arranged so that the veins form symmetrical designs, while the columns in the
niches on either side of the sanctuary apse and the entrance are of
expensive, purple granite (porphyry). The architectural sculptures in the
church - capitals, cornices and door frames - have delicate relief
decoration, often attributed to the use of a small drill, so as to create
embossed designs resembling lace around the main architectural members.All that remains of the exquisite mosaics in the church are a few
fragments. Parts of the Justinian decoration are preserved in the intrados
of the arcades in the central nave, the side aisle and the gallery vaults, and around
the edge of the apse. The decoration is non-figurative
(it
does not include human figures), consisting of floral motifs and geometric shapes
arranged on a gold background.
The surviving representations were created after the end of Iconoclasm
in 843, and were preserved because they were plastered over for as long as the
church functioned as a mosque. The semi-dome in the sanctuary apse has a
depiction of an enthroned Virgin and Child flanked by archangels; six-winged
seraphim have survived on the dome pedentives. Prelates and prophets
appear high up on the nave walls, between the windows. On the tympanum
above the door in the corridor leading from the palace to the narthex,
an enthroned Virgin and Child are shown flanked by Constantine the Great
offering an effigy of Constantinople,
and Justinian offering an effigy of Agia Sophia, so as to remind later
emperors who founded the city and
the church. The semicircular tympanum above the central (Royal) door in the narthex
bears a depiction of an emperor doing penance before the enthroned Christ,
flanked by the Virgin Mary and an archangel in medallions. The emperor is
probably Leo VI; he is shown in this position as a sign of penitence for
his fourth marriage, which was illegal under canon law.
In the north gallery there is a mosaic depiction of Leo’s VI brother,
Alexander, clothed in imperial robes, which was probably painted during his
short reign in 912-913. The east wall of the south gallery has two mosaic
votive representations of Emperors Constantine Monomachus and Zoë, dating to
around the year of Constantine’s
ascension in 1044, and of John Comnenus and Irene, from around 1118. The south
gallery also has an enormous representation of the Supplication, where Christ
is flanked by the figures of the Virgin Mary and John the Baptist interceding
for the salvation of men. This may have been sponsored by Emperor Michael VIII Palaeologus
himself, following the recovery of Constantinople
in 1261.
The monument has undergone several repairs and alterations down the
centuries. The original dome collapsed in an earthquake in 558 and was rebuilt 6
metres higher by Isidore the Younger. The enormous weight was probably not
sufficiently supported, causing the base of the dome to deform, the pillars and
buttresses to bend backwards and the east and west arch to widen. In 989 the
Armenian architect Trdat was called to Constantinople
to carry out restoration work on the west arch and parts of the dome,
which had collapsed after an earthquake. The east part of the dome
collapsed once again in 1346. In the 16th century additional repairs were
carried out, and the four minarets still seen today were added to the corners
of the building. Swiss architects Gaspar and Giuseppe Fossati oversaw another
major repair project between 1847 and 1849.
The church was the seat of the Patriarchate throughout the Byzantine period.
Following the fall of Constantinople to the Crusaders
in 1204 it became a Catholic archbishop’s cathedral, and after 1453 was
converted into a mosque. It remained a place of worship from then until 1935,
when it was declared a museum.
The city:
Constantinople, the capital city of the Byzantine
Empire, was built on the site of the ancient Greek colony of Byzantium, on the
triangular peninsula formed by the Golden Horn,
the Bosporus and the Sea
of Marmara. This was an excellent location that controlled trade
routes linking the Aegean to the Black Sea. Emperor Constantine founded Constantinople
in 330 AD as a city to rival Rome
in splendour, wealth and power. The city grew fast, leading to problems of
space and facilities, so Theodosius I extended it to the west by building new
strong walls that protected Constantinople
until the end of the Byzantine Empire.
The
city was laid out after Rome.
A main road, the Mese Odos, linked the palace to the Golden
Gate. On this road was the Forum, a circular plaza with a statue
of Constantine
mounted on a column, surrounded by public buildings. Theodosius I and Arcadius later
built more forums decorated with their own statues.
Following
the Nika riots in the 6th century, Justinian adorned Constantinople
with magnificent edifices, palaces, baths and public buildings. This time also
saw the construction of Agia Sophia (the Holy Wisdom), the church which served
as the seat of the Ecumenical Patriarchate throughout the Byzantine period.
During
the 7th and 8th centuries Constantinople faced
major problems that threw it into disarray: attacks by the Avars (a siege in
674) and Arabs (attacks in 674 and 717-718); natural disasters (a powerful,
destructive earthquake in 740); and epidemics (plague in 747). Limited building
activity resumed in the 8th and 9th century, mainly concentrated on
strengthening the city's fortifications.
With
the recovery of the Byzantine Empire from the
9th to the 11th century, Constantinople became
the most populated city in Christendom; the majority of inhabitants were
Greek-speaking, but many other ethnic groups lived alongside them, such as
Jews, Armenians, Russians, Italians merchants, Arabs and mercenaries from Western Europe and Scandinavia. Many public, private and church-owned buildings were erected at the time, with
an emphasis on establishing charitable institutions such as hospitals, nursing
homes, orphanages and schools. Higher education flourished, thanks to the care
of the state and the emergence of important scholars. This renaissance lasted
until the mid-11th century, when economic problems due to poor management set
in, compounded by the adverse outcome of imperial operations beyond the borders.
The
Crusaders left Constantinople entirely
unscathed when first passing through, but in the Fourth Crusade of 1204 the
Franks conquered and ransacked the city, slaughtering those inhabitants they
did not take prisoner or drive out. In 1261 the city was retaken by Michael
VIII Palaeologus, who rebuilt most of the monuments and the walls but proved
unable to restore the city to its former splendour and glory. Enfeebled as it
was, the empire was incapable of checking the advance of the Ottomans, and in
1453 Constantinople finally fell into their
hands.
The fall signalled the end of the empire. Nevertheless, the Byzantine intellectual
tradition remained significant, as many scholars settled in the Venetian dominions
of Crete and the Peloponnese,
as well as in European countries, conveying Greek learning to the West.
Procopius:
Prolific Byzantine
historian. Born in Caesarea Palestinae,
he studied rhetoric, sophistry and law. He moved to Constantinople
at an early age, where he practiced as an orator and lawyer. He soon entered
the circle of General Belisarius as secretary and advisor, and followed him on
many campaigns. Procopius survived the great plague of Constantinople
(541-542), which he described in detail. His writings are considered the most
important source for the Justinian period, although admittedly he is not
impartial towards the emperor; from a certain point onwards he seems to be unfavourably
biased against both Justinian and Theodora. From 549 onwards Procopius lived permanently
in Constantinople, though no information has
survived on the final years of his life.
Bibliography (2)
1. Huxley, G.L., Anthemius of Tralles. A Study of Later Greek Geometry, Cambridge Massachusetts, 1959
2. Hunger H., Βυζαντινή λογοτεχνία. Η λόγια κοσμική γραμματεία των Βυζαντινών, Μορφωτικό Ίδρυμα Εθνικής Τράπεζας, 2000
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