hout 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:
kyklike kineois]. 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: mechane], 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