In 1806, being then a member of the Select Council of the City of Philadelphia, he united with Stephen Girard and others to relieve real estate of a portion of its taxes, by transferring it to personal property, when he published a pamphlet on examination of the existing system of taxation in that city, but with no results. In 1810, when the question of the renewal of the charter of the Bank of the United States, which was to expire on the following March, came up, he took an active and earnest part in its favor, neglecting his business for three months, and publishing a series of essays on the subject. Nearly all the Democrats of the city were opposed to this, and he made himself hosts of enemies by his course. The publication of _The Olive Branch_, which was made at a critical period in the history of the country, proved to be one of the most successful books up to that time ever issued from the American press, and he regarded its preparation as one of the most important events in his life. The War of 1812–’15, between the United States and Great Britain, had developed such an acrimonious state of feeling between parties in the country, as to appear to forebode civil war. In September, 1814, Mr. Carey, in a “moment of ardent zeal and enthusiasm, was seized with a desire to make an effort by a candid publication of the numerous errors and follies on both sides to allay the public effervescence, and calm the embittered feelings of the parties.” Hence, he began the preparation of _The Olive Branch_, September 18, and the book was through the press November 6th, and was published on the 8th. It was a volume of 252 pages, 12mo. The edition of 500 copies was sold within a few weeks, and it was revised and enlarged from time to time, and in three and a half years ten editions were sold, amounting to 10,000 copies. “A greater sale probably,” as he has said, “than any book ever had in this country, except some religious ones,” up to that time. He gave permission to several parties to print the book, without payment of copyright, and editions were printed at Boston, Mass., Middlebury, Vt., and Winchester, Va. In 1818 he set laboriously and seriously to work to prepare a vindication of Ireland. Accordingly, in the following year, he published _Vindiciæ Hibernicæ; or, Ireland Vindicated_, of which a second edition was published in 1823. This is a large 8vo volume involving great research.