The northern side of the city is bounded by the harbour; and the southern is washed by the Propontis, or Sea of Marmora.

The basis of the triangle is opposed to the west, and terminates the continent of Europe.

But the admirable form and division of the circumjacent land and water cannot, without a more ample explanation, be clearly or sufficiently understood.
"The winding channel through which the waters of the Euxine flow with rapid and incessant course towards the Mediterranean received the appellation of Bosphorus, a name not less celebrated in the history than in the fables of antiquity.

A crowd of temples and of votive altars, profusely scattered along its steep and woody banks, attested the unskilfulness, the terrors, and the devotion of the Grecian navigators, who, after the example of the Argonauts, explored the dangers of the inhospitable Euxine.
On these banks tradition long preserved the memory of the palace of Phineus, infested by the obscene Harpies, and of the sylvan reign of Amycus, who defied the son of Leda to the combat of the cestus.

The straits of the Bosphorus are terminated by the Cyanean rocks, which, according to the description of the poets, had once floated on the surface of the waters, and were destined by the gods to protect the entrance of the Euxine against the eye of profane curiosity.
From the Cyanean rocks to the point and harbour of Byzantium the winding length of the Bosphorus extends about sixteen miles, and its most ordinary breadth may be computed at about one mile and a half.