[Footnote 620: Suetonius calls them organa hydralica, and they seem to
have been a musical instrument on the same principle as our present
organs, only that water was the inflating power. Vitruvius (iv. ix.)
mentions the instrument as the invention of Ctesibus of Alexandria. It is
also well described by Tertullian, De Anima, c. xiv. The pneumatic organ
appears to have been a later improvement. We have before us a contorniate
medallion, of Caracalla, from the collection of Mr. W. S. Bohn, upon which
one or other of these instruments figures. On the obverse is the bust of
the emperor in armour, laureated, with the inscription as AURELIUS
ANTONINUS PIUS AUG. BRIT. (his latest title). On the reverse is the
organ; an oblong chest with the pipes above, and a draped figure on each
side.]

[Footnote 621: A fine sand from the Nile, similar to puzzuclano, which
was strewed on the stadium; the wrestlers also rolled in it, when their
bodies were slippery with oil or perspiration.]

[Footnote 622: The words on the ticket about the emperor's neck, are
supposed, by a prosopopea, to be spoken by him. The reply is Agrippina's,
or the people's. It alludes to the punishment due to him for his
parricide. By the Roman law, a person who had murdered a parent or any
near relation, after being severely scourged, was sewed up in a sack, with
a dog, a cock, a viper, and an ape, and then thrown into the sea, or a
deep river.]

[Footnote 623: Gallos, which signifies both cocks and Gauls.]

[Footnote 624: Vindex, it need hardly be observed, was the name of the
propraetor who had set up the standard of rebellion in Gaul. The word
also signifies an avenger of wrongs, redresser of grievances; hence
vindicate, vindictive, etc.]

[Footnote 625: Aen. xii. 646.]

[Footnote 626: The Via Salaria was so called from the Sabines using it to
fetch salt from the coast. It led from Rome to the northward, near the
gardens of Sallust, by a gate of the same name, called also Quirinalis,
Agonalis, and Collina. It was here that Alaric entered.]

[Footnote 627: The Via Nomentana, so named because it led to the Sabine
town of Nomentum, joined the Via Salara at Heretum on the Tiber. It was
also called Ficulnensis. It entered Rome by the Porta Viminalis, now
called Porta Pia. It was by this road that Hannibal approached the walls
of Rome. The country-house of Nero's freedman, where he ended his days,
stood near the Anio, beyond the present c