. A machine is a combination of timbers fastened together, chiefly effica-
cious in moving great weights. Such a machine is set in motion on sci-
entific principles in circular rounds, which the Greeks call [Greek: kyklikę
kinęois]. 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 scien-
tific 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 scien-
tific refinements. But the hoisting machine has opportunities for usefulness
3 VITRUVIUS POLLIO
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: męchanę], 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. En-
gines, on the other hand, accomplish their purpose at the intelligent touch of
a single workman, as the scorpio or anisocycli when they are turned. There-
fore engines, as well as machines, are, in principle, practical necessities, with-
out 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 an-
cestors 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 con-
trivances which are so serviceable in our life. Some things, with a view to
greater convenience, they worked out by means of machines and their revo-
lutions, 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 in-
vented. 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
