Page:Vol 5 History of Mexico by H H Bancroft.djvu/429

Rh movement, it was a great achievement; but the expedition, as a factor of the war, was barren of effect.

While the American land forces were thus successfully operating on the Rio Grande the Mexican ports on the gulf were blockaded by a naval squadron, under Commodore Connor. The United States had long contended for a more liberal construction of the law of blockade than that held by European powers, and 1now proceeded to carry out the principles which had been advocated. Not only was the doctrine of a paper blockade exploded, but a special warning was ordered given to vessels appearing before blockaded ports; without such warning a vessel was not subject to seizure, and if she effected an entrance was free to depart without hinderance. The duties which devolved upon the American navy were extremely irksome, and the enforcement of the blockade difficult, owing to the nature of the Mexican ports, and the prevalence in the gulf of violent north winds, which frequently compelled the blockading ships at Vera Cruz to seek shelter to the leeward of the islands south of that port. Under these circumstances several neutral ships ran the blockade by entering the harbor by the northern channel. The small maritime commerce of Mexico was, however, destroyed.

The operations of the squadron were not always attended with success. In August and October Connor made two attempts against the port of Alvarado, which were frustrated by bad weather and the state of the river. On the second occasion the steamer McLane ran aground on the bar, and the vessels she