LUCRI´NUS LACUS(ὁ Λοκρίνος κόλπος, Strab: Lago Lucrino), a salt-water lake or lagoon, adjoining the gulf of Baiae on the coast of Campania. It was situated just at the bight or inmost point of the deep bay between Puteoli and Baiae, and was separated from the outer sea only by a narrow strip or bank of sand, in all probability of natural origin, but the construction of which was ascribed by a tradition or legend, frequently alluded to by the Roman poets, to Hercules, and the road along it is said to have been commonly called in consequence, the Via Herculea or Heraclea. According to Strabo it was 8 stadia in length, and wide enough to admit of a road for waggons. (Diod. 4.22; Strab. 5. p. 245; Lycophr. Alex. 697 ; Propert. 4.18. 4; Sil. ltal. 12.116—120.) On the other side, the Lucrine lake was separated only by a narrow space from the lake Avernus, which was, however, of a wholly different character, being a deep basin of fresh water, formed in the crater of an extinct volcano; while the Lacus Lucrinus, in common with all similar lagoons, was very shallow, and was for that reason well adapted for producing oysters and other shell-fish, for the excellence of which it was celebrated. (Hor. Epod. 2.49, Sat. 2.4. 32; Juven. 4.141; Petron. Sat. p. 424; Martial (Mart. 6.11. 5, 13.90; Varr. ap. Non. p. 216.) These oyster-beds were so valuable as to be farmed out at a high price, and Caesar was induced by the contractors to repair the dyke of Hercules for their protection. (Serv. ad Georg. 2.161.)
The Lucrine lake is otherwise known chiefly in connection with the great works of Agrippa for the construction of the so-called JULIUS PORTUS,alluded to in two well-known passages of Virgil and Horace. (Verg. G. 2.161—163; Hor. Ars Poet. 63.) It is not easy to understand exactly the nature of these works; but the object of Agrippa was obviously to obtain a perfectly secure and land-locked basin, for anchoring his fleet and for exercising his newly-raised crews and rowers. For this purpose he seems to have opened an entrance to the lake Avernus by a cut or canal from the Lucrine lake, and must, at the same time, have opened a channel from the latter into the bay, sufficiently deep for the passage of large vessels. But, together with this work, he strengthened the natural barrier of the Lucrine lake against the sea by an artificial dyke or dam, so as to prevent the waves from breaking over it as they previously did during heavy gales. (Strab. 5. p. 245; Dio Cass.; Suet. Aug. 16; Veil. Pat. 2.79; Serv. et Philargyr. ad Virg. l. c.;Plin. Nat. 36.15. s. 24.) It is clear from the accounts of these works that they were perfectly successful for a time, and they appear to have excited the greatest admiration; but they were soon abandoned, probably from the natural difficulties proving insuperable; and, from the time that the station of the Roman fleet was established at Misenum, we hear no more of the Julian Port. Even in the time of Strabo it seems to have fallen into complete disuse, for he says distinctly, that the lake Avernus was deep and well adapted for a port, but could not be used as suchon account of the Lucrine lake, which was shallow and broad, lying between it and the sea (5. p. 244). And again, a little further on (p. 245), he speaks of the latter as useless as a harbour, and accessible only to small vessels, but producing abundance of oysters. At a later period Cassiodorus ( Var. 9.6) describes it in a manner which implies that a communication was still open with the lake Avernus as well as with the sea. The two lakes are now separated by a considerable breadth of low sandy ground, but it is probable that this was formed in great part by the memorable volcanic eruption of 1538, when the hill now called Monte Nuovo, 413 feet in height and above 8000 feet in circumference, was thrown up in the course of two days, and a large part of the Lucrine lake filled up at the same time. Hence the present aspect of the lake, which is reduced to a mere marshy pool full of reeds, affords little assistance in comprehending the ancient localities. (Daubeny, On Volcanoes, pp. 208—210.) It is said that some portions of the piers of the port of Agrippa, as well as part of the dyke or bank ascribed to Hercules, are still visible under the level of the water.
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