The war of 1812-15, gave a tremendous impulse to American manufactures through the exclusion of British and other foreign products. At the close of the war, however, when American ports were thrown open to the trade of Great Britain, the manufacturers of that country, with the deliberate purpose of crushing American industries out of existence, threw vast quantities of goods into the American markets, completely swamping native productions, and making it impossible for native manufacturers to compete with the importations. It was this ruinous relapse from comparative prosperity that prompted the agitation for a protective tariff. As further evidence of British purpose to do all the damage possible to American interests, even in time of peace, it may be mentioned that when Lord Exmouth, with a powerful fleet, visited Algiers in 1816, and negotiated a treaty between the Dey--Omar, the successor of Hadgi Ali--and the kings of Sardinia and Naples, the Algerians began to show themselves again hostile to the United States within a few days after the treaty. The public sentiment of Europe, however, made it impossible for England to make longer use of those pirates to injure commercial rivals, and the British Government, in deference to that sentiment, sought a quarrel with the Dey, bombarded Algiers, and compelled the Barbary States to agree to put an end to piracy--an agreement which remained for some time a dead letter. * * * The Louisiana Purchase was crowned in 1818 by the purchase of Florida from Spain. Spanish authority in North America had long been little more than a thin disguise, behind which the British plotted and operated against the welfare of the United States. General Jackson had found it necessary in 1814 to capture Pensacola, which the English were using as a base of hostilities. Again in 1818 General Jackson invaded Florida to punish Indians who, incited by British subjects under Spanish protection, were plundering and murdering in American settlements. Jackson took by force the Spanish post of St. Marks, entered Pensacola, and attacked the fort at Barrancas, compelling it to surrender. Two British subjects who had stirred up the Indians to attack the Americans were executed. Secretary of State John Quincy Adams sustained Jackson, notwithstanding the protests of Spain, and the latter power concluded to yield to the inevitable, and sold Florida to the United States on the extinction of the various American claims for spoliation, for the satisfaction of which the United States agreed to pay $5,000,000 to the claimants. Thus all foreign authority was extinguished in the Southeast and the American flag waved from the Florida Keys to the boundaries of New Spain. CHAPTER XXX.