as follows (Fig. 17): The diameter of the building is generally under 30
feet. A door of barely comfortable height even for an average man and
surmounted by a single lintel-block gives access to a narrow passage cut
through the thickness of the wall. In this passage are, to the right, a
small niche (_c_) just large enough to hold a man, and, on the left,
a winding staircase in the wall (_d_) leading to an upper storey. The
passage itself leads into the chamber (_a_), which is circular, often
with two or three side-niches (_b b_), and roofed by corbelling, i.e. by
making each of the upper courses of stones in its wall project inwards
over the last. The upper chamber, which is rarely preserved, is similar
in form to the lower.

[Illustration: Plate II Fig. 1. MNAIDRA, DOORWAY OF ROOM H]

[Illustration: Plate II Fig. 2. THE NURAGHE OF MADRONE IN SARDINIA
To face p. 82]

[Illustration: Fig. 17. Elevation, section and plan of a _nuraghe_.
(Pinza, _Monumenti Antichi_.)]

Considerable speculation has been indulged in concerning the purpose of
the _nuraghi_. For many years they were regarded as tombs, a view which
was first combated by Nissardi at the International Congress in Rome in
1903. Further exploration since that time has placed it beyond all doubt
that the _nuraghi_ were fortified dwellings. The form of the building
itself is almost conclusive. The lowness of the door would at once put
an enemy at a disadvantage in attempting to enter; it is significant
that in the _nuraghe_ of Su Cadalanu, where the doorway was over 6 feet
in height, its breadth was so much reduced that it was necessary to
enter sideways. Arrangements were made for the closing of the entrance