DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.24#0023
— 17 —
deteriorated have been replaced, but it was inevitable that an excess of such salts should
have accumulated in the surface layer of the lower courses of the buildings, to appear as an
unsightly efflorescence when the stone was alternately wetted and dried.
During the past five years the island has been annually submerged, and the reports which
have been published from time to time show that at first there was a considerable amount of
salt efflorescence on the walls and that the greater part of the ground between the various
buildings was covered with a thin layer of efflorescent salts consisting of chlorides, sulphates,
and nitrates. The efflorescence on the walls is noted as becoming much less in subsequent years,
and, as the salt on the ground is not mentioned after the summer following the first filling of
the Keservoir, it presumably did not again occur ; at the present time, there is practically none
visible. Efflorescence only occurs above the highest level of the water, so that the salts in
the soil of the island, and in the sandstone itself, have been in part washed out, and in part
carried higher up.
When the Reservoir is full each year, algse grow on the faces of the walls, and die when the
water falls ; but only within thirty centimetres of the surface are they numerous, and here
form a white band of dead and bleached algae which some observers have taken to be a line
of efflorescent salts ; below this the remains of those which exist in greatly diminished num-
bers have imparted a greyish colour to the stone. It has been the practice to remove the algse
and the salt efflorescence annually by scrubbing with brushes, but this must also remove
any sandgrains from the face of the stone which have been already loosened by the crystalliza-
tion of the salts.
The published reports make no mention of settlement of any of the walls, though in two
instances a slight opening of pavement joints is mentioned. These favourable reports have
probably reached but a small number of readers, but on the other hand statements have been
made to the effect that the stone employed in the construction of the temples must inevitably
soften in the water, and that it is already losing its power of resistance ; such opinions have
doubtless been advanced by those who have not had all the facts before them, for it is difficult
to see what valid evidence supported this conjecture, many facts being directly opposed to it.
All the stone in foundations, whether permanently or periodically wetted by the flood, was found
in 1896 and 1901 to be perfectly sound, and the quay walls, which have been submerged
annually for twenty centuries and more, show no deterioration, but, on the contrary, contain
some of the soundest stone to be found on the Island. There is, therefore, good reason for
believing that submersion itself does no harm to the stone where the latter has been unaffected
by accumulations of salt-bearing mud-brick rubbish, and that even where it has been so affected
submersion rids the stone of the damaging salts ; above the village rubbish, the salt existing
naturally in the sandstone has caused a certain discoloration, but one or two years' submersion
appears to remove it. The action of the salt naturally present in the sandstone is, when water
reaches the stone, to disintegrate the surface to a small extent above the maximum water-level,
but this is not in any way commensurate with the extent to which the same action takes place
in the lower courses of every temple in the country from the soil-moisture facilitating the
crystallization of the salts which exist in the stone or are supplied to it from the neighbouring
soil. These questions will be dealt with in detail below.
deteriorated have been replaced, but it was inevitable that an excess of such salts should
have accumulated in the surface layer of the lower courses of the buildings, to appear as an
unsightly efflorescence when the stone was alternately wetted and dried.
During the past five years the island has been annually submerged, and the reports which
have been published from time to time show that at first there was a considerable amount of
salt efflorescence on the walls and that the greater part of the ground between the various
buildings was covered with a thin layer of efflorescent salts consisting of chlorides, sulphates,
and nitrates. The efflorescence on the walls is noted as becoming much less in subsequent years,
and, as the salt on the ground is not mentioned after the summer following the first filling of
the Keservoir, it presumably did not again occur ; at the present time, there is practically none
visible. Efflorescence only occurs above the highest level of the water, so that the salts in
the soil of the island, and in the sandstone itself, have been in part washed out, and in part
carried higher up.
When the Reservoir is full each year, algse grow on the faces of the walls, and die when the
water falls ; but only within thirty centimetres of the surface are they numerous, and here
form a white band of dead and bleached algae which some observers have taken to be a line
of efflorescent salts ; below this the remains of those which exist in greatly diminished num-
bers have imparted a greyish colour to the stone. It has been the practice to remove the algse
and the salt efflorescence annually by scrubbing with brushes, but this must also remove
any sandgrains from the face of the stone which have been already loosened by the crystalliza-
tion of the salts.
The published reports make no mention of settlement of any of the walls, though in two
instances a slight opening of pavement joints is mentioned. These favourable reports have
probably reached but a small number of readers, but on the other hand statements have been
made to the effect that the stone employed in the construction of the temples must inevitably
soften in the water, and that it is already losing its power of resistance ; such opinions have
doubtless been advanced by those who have not had all the facts before them, for it is difficult
to see what valid evidence supported this conjecture, many facts being directly opposed to it.
All the stone in foundations, whether permanently or periodically wetted by the flood, was found
in 1896 and 1901 to be perfectly sound, and the quay walls, which have been submerged
annually for twenty centuries and more, show no deterioration, but, on the contrary, contain
some of the soundest stone to be found on the Island. There is, therefore, good reason for
believing that submersion itself does no harm to the stone where the latter has been unaffected
by accumulations of salt-bearing mud-brick rubbish, and that even where it has been so affected
submersion rids the stone of the damaging salts ; above the village rubbish, the salt existing
naturally in the sandstone has caused a certain discoloration, but one or two years' submersion
appears to remove it. The action of the salt naturally present in the sandstone is, when water
reaches the stone, to disintegrate the surface to a small extent above the maximum water-level,
but this is not in any way commensurate with the extent to which the same action takes place
in the lower courses of every temple in the country from the soil-moisture facilitating the
crystallization of the salts which exist in the stone or are supplied to it from the neighbouring
soil. These questions will be dealt with in detail below.