13. But since I have been tempted into giving a description of this fortified
place, it remains to finish my account of it. Corresponding to the fane of Venus
and the spring described above, which are on the right, we have on the extreme
left the royal palace which king Mausolus built there in accordance with a plan
all his own. To the right it commands a view of the forum, the harbour, and the
entire line of fortifications, while just below it, to the left, there is a
concealed harbour, hidden under the walls in such a way that nobody could see or
know what was going on in it. Only the king himself could, in case of need, give
orders from his own palace to the oarsmen and soldiers, without the knowledge of
anybody else.
14. After the death of Mausolus, his wife Artemisia became queen, and the
Rhodians, regarding it as an outrage that a woman should be ruler of the states
of all Caria, fitted out a fleet and sallied forth to seize upon the kingdom.
When news of this reached Artemisia, she gave orders that her fleet should be
hidden away in that harbour with oarsmen and marines mustered and concealed, but
that the rest of the citizens should take their places on the city wall. After
the Rhodians had landed at the larger harbour with their well-equipped fleet,
she ordered the people on the wall to cheer them and to promise that they would
deliver up the town. Then, when they had passed inside the wall, leaving their
fleet empty, Artemisia suddenly made a canal which led to the sea, brought her
fleet thus out of the smaller harbour, and so sailed into the larger.
Disembarking her soldiers, she towed the empty fleet of the Rhodians out to sea.
So the Rhodians were surrounded without means of retreat, and were slain in the
very forum.
15. So Artemisia embarked her own soldiers and oarsmen in the ships of the
Rhodians and set forth for Rhodes. The Rhodians, beholding their own ships
approaching wreathed with laurel, supposed that their fellow-citizens were
returning victorious, and admitted the enemy. Then Artemisia, after taking
Rhodes and killing its leading men, put up in the city of Rhodes a trophy of her
victory, including two bronze statues, one representing the state of the
Rhodians, the other herself. Herself she fashioned in the act of branding the
state of the Rhodians. In later times the Rhodians, labouring under the
religious scruple which makes it a sin to remove trophies once they are
dedicated, constructed a building to surround the place, and thus by the
erection of the "Grecian Station" covered it so that nobody could see it, and
ordered that the building be called "ἁβατον."
16. Since such very powerful kings have not disdained walls built of brick,
although with their revenues and from booty they might often have had them not
only of masonry or dimension stone but even of marble, I think that one ought
not to reject buildings made of brick-work, provided that they are properly
"topped." But I shall explain why this kind of structure should not be used by
the Roman people within the city, not omitting the reasons and the grounds for
them.
17. The laws of the state forbid that walls abutting on public property
should be more than a foot and a half thick. The other walls are built of the
same thickness in order to save space. Now brick walls, unless two or three
bricks thick, cannot support more than one story; certainly not if they are only
a foot and a half in thickness. But with the present importance of the city and
the unlimited numbers of its population, it is necessary to increase the number
of dwelling-places indefinitely. Consequently, as the ground floors could not
admit of so great a number living in the city, the nature of the case has made
it necessary to find relief by making the buildings high. In these tall piles
reared with piers of stone, walls of burnt brick, and partitions of rubble work,
and provided with floor after floor, the upper stories can be
partitioned off into
rooms to very great advantage. The accommodations within the city walls being
thus multiplied as a result of the many floors high in the air, the Roman people
easily find excellent places in which to live.
18. It has now been explained how limitations of building space necessarily
forbid the employment of brick walls within the city. When it becomes necessary
to use them outside the city, they should be constructed as follows in order to
be perfect and durable. On the top of the wall lay a structure of burnt brick,
about a foot and a half in height, under the tiles and projecting like a coping.
Thus the defects usual in these walls can be avoided. For when the tiles on the
roof are broken or thrown down by the wind so that rainwater can leak through,
this burnt brick coating will prevent the crude brick from being damaged, and
the cornice-like projection will throw off the drops beyond the vertical face,
and thus the walls, though of crude brick structure, will be preserved
intact.
19. With regard to burnt brick, nobody can tell offhand whether it is of the
best or unfit to use in a wall, because its strength can be tested only after it
has been used on a roof and exposed to bad weather and time—then, if it is good
it is accepted. If not made of good clay or if not baked sufficiently, it shows
itself defective there when exposed to frosts and rime. Brick that will not
stand exposure on roofs can never be strong enough to carry its load in a wall.
Hence the strongest burnt brick walls are those which are constructed out of old
roofing tiles.
20. As for "wattle and daub" I could wish that it had never been invented.
The more it saves in time and gains in space, the greater and the more general
is the disaster that it may cause; for it is made to catch fire, like torches.
It seems better, therefore, to spend on walls of burnt brick, and be at expense,
than to save with "wattle and daub," and be in danger. And, in the stucco
covering, too, it makes cracks from the inside by the arrangement of its studs
and girts. For these swell with moisture as they are daubed, and then contract
as they dry, and, by their shrinking, cause the
solid stucco to split. But since some are obliged
to use it either to save time or money, or for partitions on an unsupported
span, the proper method of construction is as follows. Give it a high foundation
so that it may nowhere come in contact with the broken stone-work composing the
floor; for if it is sunk in this, it rots in course of time, then settles and
sags forward, and so breaks through the surface of the stucco covering.
I have now explained to the best of my ability the subject of walls, and the
preparation of the different kinds of material employed, with their advantages
and disadvantages. Next, following the guidance of Nature, I shall treat of the
framework and the kinds of wood used in it, showing how they may be procured of
a sort that will not give way as time goes on.
Chapter Nine
Timber
1. Timber should be felled between early Autumn and the time when Favonius
begins to blow. For in Spring all trees become pregnant, and they are all
employing their natural vigour in the production of leaves and of the fruits
that return every year. The requirements of that season render them empty and
swollen, and so they are weak and feeble because of their looseness of texture.
This is also the case with women who have conceived. Their bodies are not
considered perfectly healthy until the child is born; hence, pregnant slaves,
when offered for sale, are not warranted sound, because the fetus as it grows
within the body takes to itself as nourishment all the best qualities of the
mother's food, and so the stronger it becomes as the full time for birth
approaches, the less compact it allows that body to be from which it is
produced. After the birth of the child, what was heretofore taken to promote the
growth of another creature is now set free by the delivery of the newborn, and
the channels being now empty and open, the body will take it in by lapping up
its juices, and thus
becomes compact and returns to the natural strength
which it had before.
2. On the same principle, with the ripening of the fruits in Autumn the
leaves begin to wither and the trees, taking up their sap from the earth through
the roots, recover themselves and are restored to their former solid texture.
But the strong air of winter compresses and solidifies them during the time
above mentioned. Consequently, if the timber is felled on the principle and at
the time above mentioned, it will be felled at the proper season.
3. In felling a tree we should cut into the trunk of it to the very heart,
and then leave it standing so that the sap may drain out drop by drop throughout
the whole of it. In this way the useless liquid which is within will run out
through the sapwood instead of having to die in a mass of decay, thus spoiling
the quality of the timber. Then and not till then, the tree being drained dry
and the sap no longer dripping, let it be felled and it will be in the highest
state of usefulness.
4. That this is so may be seen in the case of fruit trees. When these are
tapped at the base and pruned, each at the proper time, they pour out from the
heart through the tapholes all the superfluous and corrupting fluid which they
contain, and thus the draining process makes them durable. But when the juices
of trees have no means of escape, they clot and rot in them, making the trees
hollow and good for nothing. Therefore, if the draining process does not exhaust
them while they are still alive, there is no doubt that, if the same principle
is followed in felling them for timber, they will last a long time and be very
useful in buildings.
5. Trees vary and are unlike one another in their qualities. Thus it is with
the oak, elm, poplar, cypress, fir, and the others which are most suitable to
use in buildings. The oak, for instance, has not the efficacy of the fir, nor
the cypress that of the elm. Nor in the case of other trees, is it natural that
they should be alike; but the individual kinds are effective in building, some
in one way, some in another, owing to the different properties of their
elements.
6. To begin with fir: it contains a great deal of air and fire with very
little moisture and the earthy, so that, as its natural properties are of the
lighter class, it is not heavy. Hence, its consistence being naturally stiff, it
does not easily bend under the load, and keeps its straightness when used in the
framework. But it contains so much heat that it generates and encourages decay,
which spoils it; and it also kindles fire quickly because of the air in its
body, which is so open that it takes in fire and so gives out a great flame.
7. The part which is nearest to the earth before the tree is cut down takes
up moisture through the roots from the immediate neighbourhood and hence is
without knots and is "clear." But the upper part, on account of the great heat
in it, throws up branches into the air through the knots; and this, when it is
cut off about twenty feet from the ground and then hewn, is called "knotwood"
because of its hardness and knottiness. The lowest part, after the tree is cut
down and the sapwood of the same thrown away, is split up into four pieces and
prepared for joiner's work, and so is called "clearstock."
8. Oak, on the other hand, having enough and to spare of the earthy among its
elements, and containing but little moisture, air, and fire, lasts for an
unlimited period when buried in underground structures. It follows that when
exposed to moisture, as its texture is not loose and porous, it cannot take in
liquid on account of its compactness, but, withdrawing from the moisture, it
resists it and warps, thus making cracks in the structures in which it is
used.
9. The winter oak, being composed of a moderate amount of all the elements,
is very useful in buildings, but when in a moist place, it takes in water to its
centre through its pores, its air and fire being expelled by the influence of
the moisture, and so it rots. The Turkey oak and the beech, both containing a
mixture of moisture, fire, and the earthy, with a great deal of air, through
this loose texture take in moisture to their centre and soon decay. White and
black poplar, as well as willow, linden, and the agnus
castus, containing an abundance of fire
and air, a moderate amount of moisture, and only a small amount of the earthy,
are composed of a mixture which is proportionately rather light, and so they are
of great service from their stiffness. Although on account of the mixture of the
earthy in them they are not hard, yet their loose texture makes them gleaming
white, and they are a convenient material to use in carving.
10. The alder, which is produced close by river banks, and which seems to be
altogether useless as building material, has really excellent qualities. It is
composed of a very large proportion of air and fire, not much of the earthy, and
only a little moisture. Hence, in swampy places, alder piles driven close
together beneath the foundations of buildings take in the water which their own
consistence lacks and remain imperishable forever, supporting structures of
enormous weight and keeping them from decay. Thus a material which cannot last
even a little while above ground, endures for a long time when covered with
moisture.
11. One can see this at its best in Ravenna; for there all the buildings,
both public and private, have piles of this sort beneath their foundations. The
elm and the ash contain a very great amount of moisture, a minimum of air and
fire, and a moderate mixture of the earthy in their composition. When put in
shape for use in buildings they are tough and, having no stiffness on account of
the weight of moisture in them, soon bend. But when they become dry with age, or
are allowed to lose their sap and die standing in the open, they get harder, and
from their toughness supply a strong material for dowels to be used in joints
and other articulations.
12. The hornbeam, which has a very small amount of fire and of the earthy in
its composition, but a very great proportion of air and moisture, is not a wood
that breaks easily, and is very convenient to handle. Hence, the Greeks call it
"zygia," because they make of it yokes for their draught-animals, and their word
for yoke is ξυγἁ. Cypress and pine are also just as admirable; for although they
contain an abundance of moisture mixed with
an equivalent composed of all the other elements,
and so are apt to warp when used in buildings on account of this superfluity of
moisture, yet they can be kept to a great age without rotting, because the
liquid contained within their substances has a bitter taste which by its
pungency prevents the entrance of decay or of those little creatures which are
destructive. Hence, buildings made of these kinds of wood last for an unending
period of time.
13. The cedar and the juniper tree have the same uses and good qualities,
but, while the cypress and pine yield resin, from the cedar is produced an oil
called cedar-oil. Books as well as other things smeared with this are not hurt
by worms or decay. The foliage of this tree is like that of the cypress but the
grain of the wood is straight. The statue of Diana in the temple at Ephesus is
made of it, and so are the coffered ceilings both there and in all other famous
fanes, because that wood is everlasting. The tree grows chiefly in Crete,
Africa, and in some districts of Syria.
14. The larch, known only to the people of the towns on the banks of the
river Po and the shores of the Adriatic, is not only preserved from decay and
the worm by the great bitterness of its sap, but also it cannot be kindled with
fire nor ignite of itself, unless like stone in a limekiln it is burned with
other wood. And even then it does not take fire nor produce burning coals, but
after a long time it slowly consumes away. This is because there is a very small
proportion of the elements of fire and air in its composition, which is a dense
and solid mass of moisture and the earthy, so that it has no open pores through
which fire can find its way; but it repels the force of fire and does not let
itself be harmed by it quickly. Further, its weight will not let it float in
water, so that when transported it is loaded on shipboard or on rafts made of
fir.
15. It is worth while to know how this wood was discovered. The divine
Caesar, being with his army in the neighbourhood of the Alps, and having ordered
the towns to furnish supplies, the inhabitants of a fortified stronghold there,
called Larignum, trusting in the natural strength of their defences, refused to
obey his command. So the general ordered his forces to the assault.
In front of the gate of
this stronghold there was a tower, made of beams of this wood laid in
alternating directions at right angles to each other, like a funeral pyre, and
built high, so that they could drive off an attacking party by throwing stakes
and stones from the top. When it was observed that they had no other missiles
than stakes, and that these could not be hurled very far from the wall on
account of the weight, orders were given to approach and to throw bundles of
brushwood and lighted torches at this outwork. These the soldiers soon got
together.
16. The flames soon kindled the brushwood which lay about that wooden
structure and, rising towards heaven, made everybody think that the whole pile
had fallen. But when the fire had burned itself out and subsided, and the tower
appeared to view entirely uninjured, Caesar in amazement gave orders that they
should be surrounded with a palisade, built beyond the range of missiles. So the
townspeople were frightened into surrendering, and were then asked where that
wood came from which was not harmed by fire. They pointed to trees of the kind
under discussion, of which there are very great numbers in that vicinity. And
so, as that stronghold was called Larignum, the wood was called larch. It is
transported by way of the Po to Ravenna, and is to be had in Fano, Pesaro,
Ancona, and the other towns in that neighbourhood. If there were only a ready
method of carrying this material to Rome, it would be of the greatest use in
buildings; if not for general purposes, yet at least if the boards used in the
eaves running round blocks of houses were made of it, the buildings would be
free from the danger of fire spreading across to them, because such boards can
neither take fire from flames or from burning coals, nor ignite
spontaneously.
17. The leaves of these trees are like those of the pine; timber from them
comes in long lengths, is as easily wrought in joiner's work as is the clearwood
of fir, and contains a liquid resin, of the colour of Attic honey, which is good
for consumptives.
With regard to the different kinds of timber, I have now explained of what
natural properties they appear to be composed,
and how they were produced. It remains to consider
the question why the highland fir, as it is called in Rome, is inferior, while
the lowland fir is extremely useful in buildings so far as durability is
concerned; and further to explain how it is that their bad or good qualities
seem to be due to the peculiarities of their neighbourhood, so that this subject
may be clearer to those who examine it.
Chapter Ten
Highland and Lowland Fir
1. The first spurs of the Apennines arise from the Tuscan sea between the
Alps and the most distant borders of Tuscany. The mountain range itself bends
round and, almost touching the shores of the Adriatic in the middle of the
curve, completes its circuit by extending to the strait on the other shore.
Hence, this side of the curve, sloping towards the districts of Tuscany and
Campania, lies basking in the sun, being constantly exposed to the full force of
its rays all day. But the further side, sloping towards the Upper Sea and having
a northern exposure, is constantly shrouded in shadowy darkness. Hence the trees
which grow on that side, being nourished by the moisture, not only themselves
attain to a very large size, but their fibre too, filled full of moisture, is
swollen and distended with abundance of liquid. When they lose their vitality
after being felled and hewn, the fibre retains its stiffness, and the trees as
they dry become hollow and frail on account of their porosity, and hence cannot
last when used in buildings.
2. But trees which grow in places facing the course of the sun are not of
porous fibre but are solid, being drained by the dryness; for the sun absorbs
moisture and draws it out of trees as well as out of the earth. The trees in
sunny neighbourhoods, therefore, being solidified by the compact texture of
their fibre, and not being porous from moisture, are very useful, so far as
durability goes, when they are hewn into timber. Hence the lowland firs,
being conveyed from
sunny places, are better than those highland firs, which are brought here from
shady places.
3. To the best of my mature consideration, I have now treated the materials
which are necessary in the construction of buildings, the proportionate amount
of the elements which are seen to be contained in their natural composition, and
the points of excellence and defects of each kind, so that they may be not
unknown to those who are engaged in building. Thus those who can follow the
directions contained in this treatise will be better informed in advance, and
able to select, among the different kinds, those which will be of use in their
works. Therefore, since the preliminaries have been explained, the buildings
themselves will be treated in the remaining books; and first, as due order
requires, I shall in the next book write of the temples of the immortal gods and
their symmetrical proportions.
Here ends Book II of Vitruvius; he continues
the discussion in Book III.