DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.24719#0022
6
INTRODUCTION TO THE STUDY OF BYZANTINE ARCHITECTURE.
the best buildings of ancient Rome. The lime was always well chosen, and the sand free
from foreign particles. Like the Roman mortar, it was composed of one-third rich chalk,
one-third sand, and one-third brick-dust. These proportions varied little in different countries;
but where pozzuolana was abundant, it was used in preference. Where large masses of
concrete were employed to form the foundations and cores of the walls, the courses of concrete
were laid by means of larger wooden boxes, open at top and bottom, in which, in the case of
walls, the bricks of the facing were first adjusted, and then the cement thrown in a body, and
pressed down by means of a rammer; afterwards, when the cement was properly set, the
plank sides and transverse supports were removed. The holes left upon the removal of the
cross-pieces are frequently to be observed in the walls of ancient buildings.
When concrete was used, the facing only was of brick. The walls were of great thickness,
generally more than three feet; otherwise they would have been wanting in solidity.
The mode of constructing in concrete inherited from the Romans was not applied solely
for cores of walls, but was employed in vaults, bridges, and aqueducts. In the latter the
surface of the concrete was covered with a bed of powdered charcoal mixed with lime, and
with a coating of very fine cement polished by means of an application of oil. The whole
together constituted a mass impenetrable to water, which has resisted the attacks of time.
Cisterns, in the construction of which the Byzantines surpassed the Romans, were all
formed in this manner. The vaults of these cisterns were either simply arched, or had domes
with pendentives almost always made of masses of concrete, which had the advantage of
being lighter than stone for the purpose. From cisterns, the mode of vaulting in concrete
alone, was applied to houses. Porous stone, but especially pumice-stone, was occasionally used;
sometimes the domes were constructed of pottery; for instance, in St. Yitale, at Ravenna,
where the dome is formed with urns and amphorae placed side by side, and grouted with
mortar. An example of this was found at Rome : the Circus of Caracalla was vaulted with
earthen vessels similarly arranged, forming a light yet solid system of vaulting.
The Byzantines attached so much importance to the manufacture of their mortar, that
they invented many stories relating to its use in celebrated buildings.
Codinus mentions that the mortar for the church of St. Sophia, at Constantinople, was
mixed with barley-water. The history of the bricks of the cupola, which were brought from
Rhodes, and which were so light that they floated on the surface of water, seems to be equally
apocryphal: observations made in the present day have not confirmed this tradition.
The formula for the composition of mortar was the same amongst the Byzantines as
amongst the Romans. The sand was always taken from the banks of rivers, and not from
the sea-shore. In hydraulic works the sand was omitted. The bricks were laid on the bed of
mortar after being damped. This is proved by the fact that the rough surface of the brick is
always visible on the bed of cement. The joints were always carefully pointed, so as to leave
a projecting fillet. The imposts upon which the arching was carried were generally of stone.
The Byzantines also borrowed from the Arabs a kind of mortar which is still used at
Constantinople, and is known under the name of khorasan. It is of a brown colour, and is
composed of hydraulic lime and of fine sand, and is very similar in its qualities to Portland
cement. It was by employing this mortar that the Byzantines were enabled to form so many
domes at such a slight cost.
INTRODUCTION TO THE STUDY OF BYZANTINE ARCHITECTURE.
the best buildings of ancient Rome. The lime was always well chosen, and the sand free
from foreign particles. Like the Roman mortar, it was composed of one-third rich chalk,
one-third sand, and one-third brick-dust. These proportions varied little in different countries;
but where pozzuolana was abundant, it was used in preference. Where large masses of
concrete were employed to form the foundations and cores of the walls, the courses of concrete
were laid by means of larger wooden boxes, open at top and bottom, in which, in the case of
walls, the bricks of the facing were first adjusted, and then the cement thrown in a body, and
pressed down by means of a rammer; afterwards, when the cement was properly set, the
plank sides and transverse supports were removed. The holes left upon the removal of the
cross-pieces are frequently to be observed in the walls of ancient buildings.
When concrete was used, the facing only was of brick. The walls were of great thickness,
generally more than three feet; otherwise they would have been wanting in solidity.
The mode of constructing in concrete inherited from the Romans was not applied solely
for cores of walls, but was employed in vaults, bridges, and aqueducts. In the latter the
surface of the concrete was covered with a bed of powdered charcoal mixed with lime, and
with a coating of very fine cement polished by means of an application of oil. The whole
together constituted a mass impenetrable to water, which has resisted the attacks of time.
Cisterns, in the construction of which the Byzantines surpassed the Romans, were all
formed in this manner. The vaults of these cisterns were either simply arched, or had domes
with pendentives almost always made of masses of concrete, which had the advantage of
being lighter than stone for the purpose. From cisterns, the mode of vaulting in concrete
alone, was applied to houses. Porous stone, but especially pumice-stone, was occasionally used;
sometimes the domes were constructed of pottery; for instance, in St. Yitale, at Ravenna,
where the dome is formed with urns and amphorae placed side by side, and grouted with
mortar. An example of this was found at Rome : the Circus of Caracalla was vaulted with
earthen vessels similarly arranged, forming a light yet solid system of vaulting.
The Byzantines attached so much importance to the manufacture of their mortar, that
they invented many stories relating to its use in celebrated buildings.
Codinus mentions that the mortar for the church of St. Sophia, at Constantinople, was
mixed with barley-water. The history of the bricks of the cupola, which were brought from
Rhodes, and which were so light that they floated on the surface of water, seems to be equally
apocryphal: observations made in the present day have not confirmed this tradition.
The formula for the composition of mortar was the same amongst the Byzantines as
amongst the Romans. The sand was always taken from the banks of rivers, and not from
the sea-shore. In hydraulic works the sand was omitted. The bricks were laid on the bed of
mortar after being damped. This is proved by the fact that the rough surface of the brick is
always visible on the bed of cement. The joints were always carefully pointed, so as to leave
a projecting fillet. The imposts upon which the arching was carried were generally of stone.
The Byzantines also borrowed from the Arabs a kind of mortar which is still used at
Constantinople, and is known under the name of khorasan. It is of a brown colour, and is
composed of hydraulic lime and of fine sand, and is very similar in its qualities to Portland
cement. It was by employing this mortar that the Byzantines were enabled to form so many
domes at such a slight cost.