18.
[121] Mommsen, _Eph.

Epigr._ iii, p.

111 and _Ges.

Schiften_, i.
158, 263, 371; Liebenam, _Staedteverwaltung_, 393.
Rules were also laid down occasionally to forbid balconies and similar structures which might impede the light and air in narrow streets, and it was a common rule that cemeteries and brickyards must lie outside the area of inhabitation.

At Rome too, efforts were made by various emperors to limit the height of the large tenement houses which there formed the 'insulae'.