ROMAN ARCHITECTURE—BAGGALLAY. 657 
arched ceiling, over the hot rooms and twice the hemisphere over 
the semicircular recess in which the labrum was placed. But he im- 
plies that the arched ceilings would not usually be structural ones. 
He says “ they will be more serviceable if built,” but not how that is 
to be done, and proceeds to describe? as an alternative a ceiling of 
“roofing tiles without margins” laid on iron rods or arches hung 
to a timber framing. 
The still existing barrel and hemispherical vaults over some of the 
rooms in the public baths at Pompeii are often quoted as of the re- 
publican period, but their date is very uncertain. From illustra- 
tions it would appear that they are entirely of concrete or rubble 
without brick, but the walls of the rooms are shown as having brick 
piers and lacing courses, which, according even to Doctor Middle- 
ton, would make them not earlier than the last years of the reign of 
Augustus.’ The oldest important Roman vaults to which a date can 
be assigned with tolerable certainty are those in the building called 
the Tabularium, erected against the face of the Capitoline Hill, on the 
Forum side, probably in B. C. 78. These are narrow barrel vaults 
of tufa concrete strengthened in one part at intervals with arches 
constructed with stone voussoirs, and partly, perhaps, resting on 
them. The next are those of the substructures of Caligula’s palace, 
which, if not quite so old as Caligula’s reign, must be older than 
those of the Colosseum. Middleton says they are cast concrete.¢ 
Then come the vaults behind the two lower ranges of arches of the 
Colosseum (pl. 4), which must have been erected between A. D. 
70 and 80. These are barrel vaults constructed with brick arches at 
intervals, between which they are of concrete, on the lower surface of 
which the marks of boarding are still visible. All the more elabor- 
ately constructed vaults illustrated by M. Choisy are of the second 
century or later. 
To turn from the history of construction to other matters: There 
is other evidence, besides that of Vitruvius, for the fact that the 
Romans acknowledged their indebtedness to the Etruscans for the 
form of their early temples, which appear to have had tree trunks for 
columns, widely spaced, and carrying wooden architraves. The cella 
walls were of rubble or unburnt brick, stuecoed over, and no doubt 
terminating opposite the columns of the prostyle portico in timber 
ante. The roof was of timber, covered with terra-cotta tiles; a 
terra-cotta cornice and ornaments were fixed round the eaves and 
sometimes, at least, terra-cotta or bronze statues ornamented the 
tympanum and the apex of the pediment. All was crudely painted 
in bright colors. Judging by a custom of later times, which must be 
ON Gite VareL Oss ’ Remains. I, 54. €Tbid., p. 196. 
