ADRIATIC SEA (ancient Adria or Hadria), an arm of the Mediterranean sea separating Italy from the Balkan peninsula, occupying a structural depression between the New Fold moun tain systems of the Apennines and the Dinaric Alps. The sea extends from north-west to south-east between lat. and 45' N., a length of nearly 5oo miles. Its average width is c. Iiom.; but the Strait of Otranto is only 45 miles. The Italian shore, ex cept where the Apennines fall steeply to a narrow coastal ledge between Rimini and Mt. Gargano, is low, merging in the north west into the marshes and lagoons about the delta of the Po, the basin of which is structurally a continuation of the Adriatic. The sediment brought by the river has pushed forward the coast-line for several miles within historic times. The east coast is generally rugged, and south of the Istrian peninsula, placed between the Gulf of Trieste and the Strait of Quarnero, is fringed with islands (e.g., Veglia, Cherso, Brazza and Curzola) and with many small islets and rocks which represent submerged parallel deviations of the longitudinal mountain folds. Opposite the islands of the Dal matian coast the sea is shallow, and in the extreme north rarely exceeds 25 fathoms. But between Sebenico and the Abruzzi a well marked depression occurs, with depths exceeding ioo fathoms. South of this shallower water continues, but beyond Mt. Gargano and south of Ragusa depths of over 500 fathoms are reached, and a small area of this basin falls below Boo fathoms. Opposite this deeper water, at the ioo fathom line, the islands of the Balkan coast disappear. The absence of good harbours on the Italian side contrasts with the excellent inlets of the Dalmatian coast. Here the rocks are mainly cretaceous and have characteristic features of dry barren soil and poor vegetation despite the fairly heavy rainfall. Some of the islands, however, are luxuriant with dark vegetation. The bora (north-east wind), and the prevalence of sudden squalls, are dangers to navigation in winter. Tidal move ment is slight. (See also MEDITERRANEAN.) For the "Marriage of the Adriatic," or more properly "of the sea," a ceremony formerly performed by the doge of Venice, see the article BUCENTAUR. (X.) Political Question.—Beforethe World War the Adriatic lit toral belonged to four States, Italy, Austria-Hungary, Montenegro and Albania, and in practice to the two first. In negotiating the "secret" _Treaty of London of April 26, 1915, the Italian Govern ment aimed at securing, in return for Italy's entrance into the war on the side of the Allies, the conversion of the Adriatic into an Italian lake—il nostro mare.
Article 4 of that treaty provided that "all Istria up to the Quarnero and comprising Volosca, just beyond Abbazia and the Istrian islands of Cherso, Lussin . . . and the adjoining islets" with Castua and Mattuglie, the station for Abbazia, should be come Italian. Article 5 declared that Italy "shall equally receive the province of Dalmatia . . . comprising Lisarica and Tribanj in the north" to a line as far south as Cape Planca (Plae), between Sebenico and Trail (Trogir), on the mainland, with "all the island's . . . from Premuda, Selve (Silba) and Pago in the north to Meleda in the south, comprising Lissa, Lesina, Curzola, Lagosta (Lastovo) and Pelagosa, with the solitary exception of Great Zirona (Veli Drvenik) and Small Zirona (Mali Drvenik), Bua (Ciovo), Solta and Brazza." The whole coast from Cape Planca to the "southern root" of the peninsula of Sabbioncello and from a point Iokm. to the south of Ragusa Vecchia (Cavtat) to the river Viosa (north of Valona), except Montenegro, and all the non-Italian islands were to be neutralized. The rest of the Dalmatian coast, besides Fiume and the islands of Veglia and Arbe in the north, were to go to Croatia, Serbia and Monte negro, besides the Albanian roadstead of San Giovanni di Medua (the landing-place for Scutari) ; but Durazzo was to be Albanian.
Article 6 further conferred upon Italy "the entire sovereignity over Valona, the island of Saseno and a territory sufficiently extended to assure the defence of those points" (from the Viosa . . . approximately to the northern frontier of the district of Chimara). Article 7 neutralized the coast south of the above as far as Cape Stylos opposite Corfu. This treaty violated every principle of nationality ; it assigned to Italy provinces overwhelm ingly Slav (for the Italian population of Dalmatia was only 3.5%), it dismembered Albania and would have created a new Irredentism far more powerful than that which Italy had fought to cure. The entrance of the United States into the war made the treaty a dead letter, although Baron Sonnino, then Italian Minister of Foreign Affairs, still clung to it, for President Wilson refused to be bound by it, and even some Italians, notably Bissolati and Prof. Salvemini disapproved of it.
Thus began the wearisome "Adriatic question," which at times threatened war between Italy and the Yugoslays, and attempts were made by British publicists, notably Messrs. Steed and Seton-Watson, to bring about an agreement, the "Pact of Rome," between the two races. The departure of Sig. Orlando, then the Italian premier, and Baron Sonnino from the Paris Conference was due to this question, which was not regulated till the Treaty of Rapallo between the Italians and the Yugoslays on Nov. 12, 192o, largely the work of Signor Giolitti and Count Sforza, who had meanwhile become Premier and Minister of Foreign Affairs. In Dalmatia, Italy obtained only Zara—the one overwhelmingly Italian town—with an enclave which included the Albanian settle ment of Borgo Erizzo—and the island of Lagosta. Italy kept the whole of Istria (despite its large Slav minority) with the islands of Cherso and Lussin and that of Pelagosa. "All the other islands which belonged to the former Austro-Hungarian Monarchy" were "recognized as forming part of the Kingdom of the Serbs, Croats and Slovenes." By article 4, both States recognized the full liberty and inde pendence of the State of Fiume (q.v.), consisting of the corpus separatum (the city) and a corridor south of Castua (which became Yugoslav) connecting it with Volosca and Abbazia. Sig. Giolitti evacuated Albania, where Italy retains only the island of Saseno. Mussolini observed the Rapallo Treaty and subsequently settled the question of Fiume, which is now Italian.
The Adriatic is described at Belgrade, no less than in Rome, as "our sea," but the keys of the mouth of the Adriatic, Brindisi and Saseno, are in Italian hands.