The apprehension excited by the proximity of the Boca Grande to the town determined the court of Madrid, after the English expedition, to shut up the entrance along a distance of 2640 varas. From two and a half to three fathoms of water were found; and a wall, or rather a dyke, in stone, from fifteen to twenty feet high, was raised on piles. The slope on the side of the water is unequal, and seldom 45 degrees. This immense work was completed under the Viceroy Espeleta in 1795. But art could not vanquish nature; the sea is unceasingly though gradually silting up the Boca Chica, while it labours unceasingly to open and enlarge the Boca Grande. The currents which, during a great part of the year, especially when the bendavales blow with violence, ascend from south-west to north-east, throw sand into the Boca Chica, and even into the bay itself. The passage, which is from seventeen to eighteen fathoms deep, becomes more and more narrow,* and if a regular cleansing be not established by dredging machines, vessels will not be able to enter without risk. (* At the foot of the two forts San Jose and San Fernando, constructed for the defence of the Boca Chica, it may be seen how much the land has gained upon the sea. Necks of land are formed on both sides, and also before the Castillo del Angel which, northward, commands the fort of San Fernando.) It is this small entrance which should have been closed; its opening is only 250 toises, and the passage or navigable channel is 110 toises. If it should one day be determined to abandon the Boca Chica, and re-establish the Boca Grande in the state which nature seems to prescribe, new fortifications must be constructed on the south-south-west of the town. This fortress has always required great pecuniary outlays to keep it up.