The Ten Books on Architecture
hours, until it comes to the points in Libra, where it makes the hours
equinoctial once more.
15. Finally, the opening comes down more rapidly through Scorpio and
Sagittarius, and on its return from its revolution to the end of the
first eighth of Capricornus, the velocity of the stream renews once more
the short hours of the winter solstice.
The rules and forms of construction employed in designing dials have now
been described as well as I could. It remains to give an account of
machines and their principles. In order to make my treatise on
architecture complete, I will begin to write on this subject in the
following book.
BOOK X
INTRODUCTION
1. In the famous and important Greek city of Ephesus there is said to be
an ancient ancestral law, the terms of which are severe, but its justice
is not inequitable. When an architect accepts the charge of a public
work, he has to promise what the cost of it will be. His estimate is
handed to the magistrate, and his property is pledged as security until
the work is done. When it is finished, if the outlay agrees with his
statement, he is complimented by decrees and marks of honour. If no more
than a fourth has to be added to his estimate, it is furnished by the
treasury and no penalty is inflicted. But when more than one fourth has
to be spent in addition on the work, the money required to finish it is
taken from his property.
2. Would to God that this were also a law of the Roman people, not
merely for public, but also for private buildings. For the ignorant
would no longer run riot with impunity, but men who are well qualified
by an exact scientific training would unquestionably adopt the
profession of architecture. Gentlemen would not be misled into limitless
and prodigal expenditure, even to ejectments from their estates, and the
architects themselves could be forced, by fear of the penalty, to be
more careful in calculating and stating the limit of expense, so that
gentlemen would procure their buildings for that which they had
expected, or by adding only a little more. It is true that men who can
afford to devote four hundred thousand to a work may hold on, if they
have to add another hundred thousand, from the pleasure which the hope
of finishing it gives them; but if they are loaded with a fifty per cent
increase, or with an even greater expense, they lose hope, sacrifice
what they have already spent, and are compelled to leave off, broken in
fortune and in spirit.
3. This fault appears not only in the matter of buildings, but also in
the shows given by magistrates, whether of gladiators in the forum or of
plays on the stage. Here neither delay nor postponement is permissible,
but the necessities of the case require that everything should be ready
at a fixed time,--the seats for the audience, the awning drawn over
them, and whatever, in accordance with the customs of the stage, is
provided by machinery to please the eye of the people. These matters
require careful thought and planning by a well trained intellect; for
none of them can be accomplished without machinery, and without hard
study skilfully applied in various ways.
4. Therefore, since such are our traditions and established practices,
it is obviously fitting that the plans should be worked out carefully,
and with the greatest attention, before the structures are begun.
Consequently, as we have no law or customary practice to compel this,
and as every year both praetors and aediles have to provide machinery
for the festivals, I have thought it not out of place, Emperor, since I
have treated of buildings in the earlier books, to set forth and teach
in this, which forms the final conclusion of my treatise, the principles
which govern machines.
CHAPTER I
MACHINES AND IMPLEMENTS
1. A machine is a combination of timbers fastened together, chiefly
efficacious in moving great weights. Such a machine is set in motion on
scientific principles in circular rounds, which the Greeks call [Greek:
kyklikê kinêois]. There is, however, a class intended for climbing,
termed in Greek [Greek: akrobatikon], another worked by air, which with
them is called [Greek: pneumatikon], and a third for hoisting; this the
Greeks named [Greek: baroulkos]. In the climbing class are machines so
disposed that one can safely climb up high, by means of timbers set up
on end and connected by crossbeams, in order to view operations. In the
pneumatic class, air is forced by pressure to produce sounds and tones
as in an [Greek: organon].
2. In the hoisting class, heavy weights are removed by machines which
raise them up and set them in position. The climbing machine displays no
scientific principle, but merely a spirit of daring. It is held together
by dowels and crossbeams and twisted lashings and supporting props. A
machine that gets its motive power by pneumatic pressure will produce
pretty effects by scientific refinements. But the hoisting machine has
opportunities for usefulness which are greater and full of grandeur, and
it is of the highest efficacy when used with intelligence.
3. Some of these act on the principle of the [Greek: mêchanê], others on
that of the [Greek: organon]. The difference between "machines" and
"engines" is obviously this, that machines need more workmen and greater
power to make them take effect, as for instance ballistae and the beams
of presses. Engines, on the other hand, accomplish their purpose at the
intelligent touch of a single workman, as the scorpio or anisocycli when
they are turned. Therefore engines, as well as machines, are, in
principle, practical necessities, without which nothing can be
unattended with difficulties.
4. All machinery is derived from nature, and is founded on the teaching
and instruction of the revolution of the firmament. Let us but consider
the connected revolutions of the sun, the moon, and the five planets,
without the revolution of which, due to mechanism, we should not have
had the alternation of day and night, nor the ripening of fruits. Thus,
when our ancestors had seen that this was so, they took their models
from nature, and by imitating them were led on by divine facts, until
they perfected the contrivances which are so serviceable in our life.
Some things, with a view to greater convenience, they worked out by
means of machines and their revolutions, others by means of engines, and
so, whatever they found to be useful for investigations, for the arts,
and for established practices, they took care to improve step by step on
scientific principles.
5. Let us take first a necessary invention, such as clothing, and see
how the combination of warp and woof on the loom, which does its work on
the principle of an engine, not only protects the body by covering it,
but also gives it honourable apparel. We should not have had food in
abundance unless yokes and ploughs for oxen, and for all draught
animals, had been invented. If there had been no provision of
windlasses, pressbeams, and levers for presses, we could not have had
the shining oil, nor the fruit of the vine to give us pleasure, and
these things could not be transported on land without the invention of
the mechanism of carts or waggons, nor on the sea without that of ships.
6. The discovery of the method of testing weights by steelyards and
balances saves us from fraud, by introducing honest practices into life.
There are also innumerable ways of employing machinery about which it
seems unnecessary to speak, since they are at hand every day; such as
mills, blacksmiths' bellows, carriages, gigs, turning lathes, and other
things which are habitually used as general conveniences. Hence, we
shall begin by explaining those that rarely come to hand, so that they
may be understood.
CHAPTER II
HOISTING MACHINES
1. First we shall treat of those machines which are of necessity made
ready when temples and public buildings are to be constructed. Two
timbers are provided, strong enough for the weight of the load. They are
fastened together at the upper end by a bolt, then spread apart at the
bottom, and so set up, being kept upright by ropes attached at the upper
ends and fixed at intervals all round. At the top is fastened a block,
which some call a "rechamus." In the block two sheaves are enclosed,
turning on axles. The traction rope is carried over the sheave at the
top, then let fall and passed round a sheave in a block below. Then it
is brought back to a sheave at the bottom of the upper block, and so it
goes down to the lower block, where it is fastened through a hole in
that block. The other end of the rope is brought back and down between
the legs of the machine.
2. Socket-pieces are nailed to the hinder faces of the squared timbers
at the point where they are spread apart, and the ends of the windlass
are inserted into them so that the axles may turn freely. Close to each
end of the windlass are two holes, so adjusted that handspikes can be
fitted into them. To the bottom of the lower block are fastened shears
made of iron, whose prongs are brought to bear upon the stones, which
have holes bored in them. When one end of the rope is fastened to the
windlass, and the latter is turned round by working the handspikes, the
rope winds round the windlass, gets taut, and thus it raises the load to
the proper height and to its place in the work.
3. This kind of machinery, revolving with three sheaves, is called a
trispast. When there are two sheaves turning in the block beneath and
three in the upper, the machine is termed a pentaspast. But if we have
to furnish machines for heavier loads, we must use timbers of greater
length and thickness, providing them with correspondingly large bolts at
the top, and windlasses turning at the bottom. When these are ready,
let forestays be attached and left lying slack in front; let the
backstays be carried over the shoulders of the machine to some distance,
and, if there is nothing to which they can be fastened, sloping piles
should be driven, the ground rammed down all round to fix them firmly,
and the ropes made fast to them.
4. A block should then be attached by a stout cord to the top of the
machine, and from that point a rope should be carried to a pile, and to
a block tied to the pile. Let the rope be put in round the sheave of
this block, and brought back to the block that is fastened at the top of
the machine. Round its sheave the rope should be passed, and then should
go down from the top, and back to the windlass, which is at the bottom
of the machine, and there be fastened. The windlass is now to be turned
by means of the handspikes, and it will raise the machine of itself
without danger. Thus, a machine of the larger kind will be set in
position, with its ropes in their places about it, and its stays
attached to the piles. Its blocks and traction ropes are arranged as
described above.
5. But if the loads of material for the work are still more colossal in
size and weight, we shall not entrust them to a windlass, but set in an
axle-tree, held by sockets as the windlass was, and carrying on its
centre a large drum, which some term a wheel, but the Greeks call it
[Greek: amphiesis] or [Greek: perithêkion].
6. And the blocks in such machines are not arranged in the same, but in
a different manner; for the rows of sheaves in them are doubled, both at
the bottom and at the top. The traction rope is passed through a hole in
the lower block, in such a way that the two ends of the rope are of
equal length when it is stretched out, and both portions are held there
at the lower block by a cord which is passed round them and lashed so
that they cannot come out either to the right or the left. Then the ends
of the rope are brought up into the block at the top from the outside,