The Ten Books on Architecture
such depressions is not great, the water may be carried round
circuitously; but if the valleys are extensive, the course will be
directed down their slope. On reaching the bottom, a low substructure is
built so that the level there may continue as long as possible. This
will form the "venter," termed [Greek: Koilia] by the Greeks. Then, on
reaching the hill on the opposite side, the length of the venter makes
the water slow in swelling up to rise to the top of the hill.
6. But if there is no such venter made in the valleys, nor any
substructure built on a level, but merely an elbow, the water will break
out, and burst the joints of the pipes. And in the venter, water
cushions must be constructed to relieve the pressure of the air. Thus,
those who have to conduct water through lead pipes will do it most
successfully on these principles, because its descents, circuits,
venters, and risings can be managed in this way, when the level of the
fall from the sources to the city is once obtained.
7. It is also not ineffectual to build reservoirs at intervals of 24,000
feet, so that if a break occurs anywhere, it will not completely ruin
the whole work, and the place where it has occurred can easily be
found; but such reservoirs should not be built at a descent, nor in the
plane of a venter, nor at risings, nor anywhere in valleys, but only
where there is an unbroken level.
8. But if we wish to spend less money, we must proceed as follows. Clay
pipes with a skin at least two digits thick should be made, but these
pipes should be tongued at one end so that they can fit into and join
one another. Their joints must be coated with quicklime mixed with oil,
and at the angles of the level of the venter a piece of red tufa stone,
with a hole bored through it, must be placed right at the elbow, so that
the last length of pipe used in the descent is jointed into the stone,
and also the first length of the level of the venter; similarly at the
hill on the opposite side the last length of the level of the venter
should stick into the hole in the red tufa, and the first of the rise
should be similarly jointed into it.
9. The level of the pipes being thus adjusted, they will not be sprung
out of place by the force generated at the descent and at the rising.
For a strong current of air is generated in an aqueduct which bursts its
way even through stones unless the water is let in slowly and sparingly
from the source at first, and checked at the elbows or turns by bands,
or by the weight of sand ballast. All the other arrangements should be
made as in the case of lead pipes. And ashes are to be put in beforehand
when the water is let in from the source for the first time, so that if
any of the joints have not been sufficiently coated, they may be coated
with ashes.
10. Clay pipes for conducting water have the following advantages. In
the first place, in construction:--if anything happens to them, anybody
can repair the damage. Secondly, water from clay pipes is much more
wholesome than that which is conducted through lead pipes, because lead
is found to be harmful for the reason that white lead is derived from
it, and this is said to be hurtful to the human system. Hence, if what
is produced from it is harmful, no doubt the thing itself is not
wholesome.
11. This we can exemplify from plumbers, since in them the natural
colour of the body is replaced by a deep pallor. For when lead is
smelted in casting, the fumes from it settle upon their members, and day
after day burn out and take away all the virtues of the blood from their
limbs. Hence, water ought by no means to be conducted in lead pipes, if
we want to have it wholesome. That the taste is better when it comes
from clay pipes may be proved by everyday life, for though our tables
are loaded with silver vessels, yet everybody uses earthenware for the
sake of purity of taste.
12. But if there are no springs from which we can construct aqueducts,
it is necessary to dig wells. Now in the digging of wells we must not
disdain reflection, but must devote much acuteness and skill to the
consideration of the natural principles of things, because the earth
contains many various substances in itself; for like everything else, it
is composed of the four elements. In the first place, it is itself
earthy, and of moisture it contains springs of water, also heat, which
produces sulphur, alum, and asphalt; and finally, it contains great
currents of air, which, coming up in a pregnant state through the porous
fissures to the places where wells are being dug, and finding men
engaged in digging there, stop up the breath of life in their nostrils
by the natural strength of the exhalation. So those who do not quickly
escape from the spot, are killed there.
13. To guard against this, we must proceed as follows. Let down a
lighted lamp, and if it keeps on burning, a man may make the descent
without danger. But if the light is put out by the strength of the
exhalation, then dig air shafts beside the well on the right and left.
Thus the vapours will be carried off by the air shafts as if through
nostrils. When these are finished and we come to the water, then a wall
should be built round the well without stopping up the vein.
14. But if the ground is hard, or if the veins lie too deep, the water
supply must be obtained from roofs or higher ground, and collected in
cisterns of "signinum work." Signinum work is made as follows. In the
first place, procure the cleanest and sharpest sand, break up lava into
bits of not more than a pound in weight, and mix the sand in a mortar
trough with the strongest lime in the proportion of five parts of sand
to two of lime. The trench for the signinum work, down to the level of
the proposed depth of the cistern, should be beaten with wooden beetles
covered with iron.
15. Then after having beaten the walls, let all the earth between them
be cleared out to a level with the very bottom of the walls. Having
evened this off, let the ground be beaten to the proper density. If such
constructions are in two compartments or in three so as to insure
clearing by changing from one to another, they will make the water much
more wholesome and sweeter to use. For it will become more limpid, and
keep its taste without any smell, if the mud has somewhere to settle;
otherwise it will be necessary to clear it by adding salt.
In this book I have put what I could about the merits and varieties of
water, its usefulness, and the ways in which it should be conducted and
tested; in the next I shall write about the subject of dialling and the
principles of timepieces.
BOOK IX
INTRODUCTION
1. The ancestors of the Greeks have appointed such great honours for the
famous athletes who are victorious at the Olympian, Pythian, Isthmian,
and Nemean games, that they are not only greeted with applause as they
stand with palm and crown at the meeting itself, but even on returning
to their several states in the triumph of victory, they ride into their
cities and to their fathers' houses in four-horse chariots, and enjoy
fixed revenues for life at the public expense. When I think of this, I
am amazed that the same honours and even greater are not bestowed upon
those authors whose boundless services are performed for all time and
for all nations. This would have been a practice all the more worth
establishing, because in the case of athletes it is merely their own
bodily frame that is strengthened by their training, whereas in the case
of authors it is the mind, and not only their own but also man's in
general, by the doctrines laid down in their books for the acquiring of
knowledge and the sharpening of the intellect.
2. What does it signify to mankind that Milo of Croton and other victors
of his class were invincible? Nothing, save that in their lifetime they
were famous among their countrymen. But the doctrines of Pythagoras,
Democritus, Plato, and Aristotle, and the daily life of other learned
men, spent in constant industry, yield fresh and rich fruit, not only to
their own countrymen, but also to all nations. And they who from their
tender years are filled with the plenteous learning which this fruit
affords, attain to the highest capacity of knowledge, and can introduce
into their states civilized ways, impartial justice, and laws, things
without which no state can be sound.
3. Since, therefore, these great benefits to individuals and to
communities are due to the wisdom of authors, I think that not only
should palms and crowns be bestowed upon them, but that they should even
be granted triumphs, and judged worthy of being consecrated in the
dwellings of the gods.
Of their many discoveries which have been useful for the development of
human life, I will cite a few examples. On reviewing these, people will
admit that honours ought of necessity to be bestowed upon them.
4. First of all, among the many very useful theorems of Plato, I will
cite one as demonstrated by him. Suppose there is a place or a field in
the form of a square and we are required to double it. This has to be
effected by means of lines correctly drawn, for it will take a kind of
calculation not to be made by means of mere multiplication. The
following is the demonstration. A square place ten feet long and ten
feet wide gives an area of one hundred feet. Now if it is required to
double the square, and to make one of two hundred feet, we must ask how
long will be the side of that square so as to get from this the two
hundred feet corresponding to the doubling of the area. Nobody can find
this by means of arithmetic. For if we take fourteen, multiplication
will give one hundred and ninety-six feet; if fifteen, two hundred and
twenty-five feet.
5. Therefore, since this is inexplicable by arithmetic, let a diagonal
line be drawn from angle to angle of that square of ten feet in length
and width, dividing it into two triangles of equal size, each fifty feet
in area. Taking this diagonal line as the length, describe another
square. Thus we shall have in the larger square four triangles of the
same size and the same number of feet as the two of fifty feet each
which were formed by the diagonal line in the smaller square. In this
way Plato demonstrated the doubling by means of lines, as the figure
appended at the bottom of the page will show.
6. Then again, Pythagoras showed that a right angle can be formed
without the contrivances of the artisan. Thus, the result which
carpenters reach very laboriously, but scarcely to exactness, with their
squares, can be demonstrated to perfection from the reasoning and
methods of his teaching. If we take three rules, one three feet, the
second four feet, and the third five feet in length, and join these
rules together with their tips touching each other so as to make a
triangular figure, they will form a right angle. Now if a square be
described on the length of each one of these rules, the square on the
side of three feet in length will have an area of nine feet; of four
feet, sixteen; of five, twenty-five.
7. Thus the area in number of feet made up of the two squares on the
sides three and four feet in length is equalled by that of the one
square described on the side of five. When Pythagoras discovered this
fact, he had no doubt that the Muses had guided him in the discovery,
and it is said that he very gratefully offered sacrifice to them.
This theorem affords a useful means of measuring many things, and it is
particularly serviceable in the building of staircases in buildings, so
that the steps may be at the proper levels.
8. Suppose the height of the story, from the flooring above to the
ground below, to be divided into three parts. Five of these will give
the right length for the stringers of the stairway. Let four parts, each