wind raises the sea on the coast between Tarracina and Circeo, the water would be driven into the basin of the Pomptine marshes instead of flowing out.  There would therefore be no sufficient fall of water to keep the channel clear, even if the head of the cut, where it originated in the Tiber, were high enough; and that is doubtful.  The scheme was probably a canal, which with some locks might be practicable; but if the work could be accomplished, it would probably have no commercial advantages.]

[Footnote 586:  Pometia is the common Roman form, from which comes the name of the Pometinae, or Pomptinae Paludes, now the Pontine Paludi; the site of Pometia is uncertain.  That Caesar intended to accomplish the drainage of this tract is mentioned by Dion Cassius and Suetonius.

Setia (Sezza), noted for its wine, is on the Volscian hills (the Monti Lepini), and on the eastern margin of the marshes.  The physical condition of this tract is described by Prony, in his “Description Hydrographique et Historique des Marais Pontins,” 4to.  Paris, 1822; the work is accompanied by a volume of plans and sections and a map of the district.  A sketch of the physical character of this district, and of the various attempts to drain it, is also given in the ’Penny Cyclopaedia,’—­art. Pomptine Marshes.  See also Westphal’s two valuable maps of the Campagna di Roma, and his accompanying Memoir, Berlin and Stettin, 1829.]

[Footnote 587:  Ostia, the old port of Rome, on the east bank of the Tiber near the mouth of the river.  The present Ostia is somewhat farther inland, and was built in the ninth century by Pope Gregory the Fourth.  There are extensive remains of the old town, but they are in a very decayed condition.  “Numerous shafts of columns, which are scattered about in all directions, remains of the walls of extensive buildings, and large heaps of rubbish covered with earth and overgrown with grass, give some, though a faint, idea of the splendour, of the ancient city, which at the time of its greatest splendour, at the beginning of our era, had eighty thousand inhabitants.” (Westphal, Die Roemische Kampagne, p. 7.)]

[Footnote 588:  The reformation of the Kalendar was effected in B.C. 46.  Dion Cassius (43. c. 26) says that Caesar was instructed on this subject during his residence at Alexandria in Egypt.  The Egyptians had a year of 365 days from a very early date (Herodotus, ii. 4).  In this year (B.C. 46) Caesar intercalated two months of 67 days between November and December, and as this was the year in which, according to the old fashion, the intercalary month of 23 days had been inserted in February, the whole intercalation in this year was 90 days.  Caesar made the reformed year consist of 365 days, and he directed one day to be intercalated in every fourth year (quarto quoque anno) in order that the civil year, which began on the 1st of January, might agree with the solar year.  The old practice of