ward from the standpoint of
higher ideas born of the multiplication of the arts, they gave up huts
and began to build houses with foundations, having brick or stone
walls, and roofs of timber and tiles; next, observation and application
led them from fluctuating and indefinite conceptions to definite rules
of symmetry. Perceiving that nature had been lavish in the bestowal of
timber and bountiful in stores of building material, they treated this
like careful nurses, and thus developing the refinements of life,
embellished them with luxuries. Therefore I shall now treat, to the best
of my ability, of the things which are suitable to be used in buildings,
showing their qualities and their excellencies.

8. Some persons, however, may find fault with the position of this book,
thinking that it should have been placed first. I will therefore explain
the matter, lest it be thought that I have made a mistake. Being engaged
in writing a complete treatise on architecture, I resolved to set forth
in the first book the branches of learning and studies of which it
consists, to define its departments, and to show of what it is composed.
Hence I have there declared what the qualities of an architect should
be. In the first book, therefore, I have spoken of the function of the
art, but in this I shall discuss the use of the building materials which
nature provides. For this book does not show of what architecture is
composed, but treats of the origin of the building art, how it was
fostered, and how it made progress, step by step, until it reached its
present perfection.

9. This book is, therefore, in its proper order and place.

I will now return to my subject, and with regard to the materials suited
to the construction of buildings will consider their natural formation
and in what proportions their elementary constituents were combined,
making it all clear and not obscure to my readers. For there is no kind
of material, no body, and no thing that can be produced or conceived of,
which is not made up of elementary particles; and nature does not admit
of a truthful exploration in accordance with the doctrines of the
physicists without an accurate demonstration of the primary causes of
things, showing how and why they are as they are.

CHAPTER II

ON THE PRIMORDIAL SUBSTANCE ACCORDING TO THE PHYSICISTS

1. First of all Thales thought that water was the primordial substance
of all things. Heraclitus of Ephesus, surnamed b