Physics - Mechanics
Physics
In Byzantium physics was not an independent
branch of science, as it is today, but belonged to the sciences of mathematics
and mechanics. Later, in Middle and Late
Byzantium, physics supplemented other subjects, such as arithmetic, geometry,
music and astronomy. Typical
cases of scientists who dealt with physics are the two architects of Agia
Sophia, Anthemius of Tralles and Isidore of Miletus. Anthemius came from a
family of scholars. Born in Alexandria,
he was educated under the philosopher, astronomer and orator Ammonius.
Several
authors refer to his particular bent for mathematics and engineering, as well
as to his scientific work in both fields. More specifically, in mathematics he
developed the theory of ellipses and co-wrote On the Parabola, a work analyzing how parabolas are made; his
contribution to developing the theory of conic sections is also regarded as
significant.
In the field of engineering he set out his theory of concave
mirrors in On Wondrous Machines, where he explains how solar rays
can be concentrated in one spot with the aid of a concave mirror, regardless of
season and time. There is an anecdote about Anthemius that shows how capable he
was at finding dynamic solutions: 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.
Isidore, the other Agia Sophia
architect, had a broad education. He was as good a mathematician as Anthemius,
and saw to the publication of Aristotle’s works. One of his students - possibly
the engineer and astronomer Leontes - rescued the fifteenth book of Euclid. Furthermore, the
interest Anthemius took in engineering is evident from his preoccupation with Geodesica, a lost work by Hero on the construction
of domes.
Mechanical Engineering
Inventions in engineering were not disseminated in Late Antiquity; they
arose as the result of ordinary artisans or slaves improvising in local
workshops. This meant that any idea was left without being further developed,
improved or put into mass production.
One
exception was Pappus, a Greek mathematician, geometer and engineer who lived in
Alexandria in
the 3rd-4th century. In his work Synagoge
(or Collection) he gathered together all
the devices thus far considered landmarks in the history of engineering:
levers, catapults, water hoisting machinery, "automatons" (automatic
devices), 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. One such
device with hydraulic and mechanical moving parts was the three-story clock of
Gaza, as described by the orator Procopius in the early years of the 6th
century: a mechanical trumpet call every hour was accompanied by movement of a
statue of Helios (the sun god) to point at one of twelve doors in the upper floor,
which opened to reveal a sculpture ensemble depicting one of the twelve labours
of Hercules. The royal throne in the palace
of Magnaura was equipped
with similar systems too. According to the descriptions by both Emperor
Constantine Porphyrogenitus and Liutprand, later Bishop of Cremona, the throne
rose up to the top of the formal hall, while at the same time instruments
played music, metal lions opened their mouths and roared, and birds sang on
silver trees above the throne. Thus 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. From the 9th century onwards, however, engineers worked exclusively
for the emperor and the palace, as is testified by the elaborate mechanism at
the Byzantine emperor’s throne.
Geometers knew how to use a surveying instrument
called the dioptra. A seventh or eighth century topographer known to us as Hero
co-wrote a book on how to solve practical problems involved in calculating
distances between points and surfaces using the dioptra, which is considered
the precursor of today's theodolite. The astrolabe was the chief instrument of
astronomy, used to calculate the azimuth and determine the distances between
celestial bodies. Important Byzantine scholars such as John Philoponus,
Nicephorus Gregoras and Isaac Argyros wrote on the astrolabe and its use. The only
surviving Byzantine astrolabe, with an inscription dating it to 1062, is held
in the Museum of Brescia.
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