Cooper's interest in the navy led him also to write a series of lives of officers who had been prominent in its history. The first of these appeared originally in "Graham's Magazine" for October, 1842, and the others are scattered through the volumes of that year and the years succeeding. In 1846 they were published in book form. Among them was a life of Perry. In this he took occasion to reaffirm what he had previously said about the battle of Lake Erie. But the injustice which had been done to him did not lead him to treat with injustice the man whose life he was writing, though it was impossible for him to say what would be satisfactory to Perry's partisans without falsifying what he believed to be the truth. In spite of the numerous attacks made upon it the "Naval History" was successful, as success is measured in technical works of this kind. A second edition, revised and corrected, appeared in April, 1840, and in 1847 a third edition was published. At the time of his death Cooper was projecting a continuation of it, and had gathered together materials for that purpose. The original work ended with the close of the last war with Great Britain. He intended to bring it down to the end of the Mexican War. This was done by another after his death. In 1853 a new edition of the "Naval History" appeared with a continuation prepared by the Reverend Charles W. McHarg. The matter that Cooper had collected was used, but there was very little in what was added that was of his own composition. Of the original work, it is safe to say, that for the period which it covers it is little likely to be superseded as the (p. 230) standard history of the American navy. Later investigation may show some of the author's assertions to be erroneous. Some of his conclusions may turn out as mistaken as have his prophecies about the use of steam in war vessels. But such defects, assuming that they exist, are more than counterbalanced by advantages which make it a final authority on points that can never again be so fully considered. Many sources of information which were then accessible no longer exist. The men who shared in the scenes described, and who communicated information directly to Cooper, have all passed away. These are losses that can never be replaced, even were it reasonable to expect that the same practical knowledge, the same judicial spirit, and the same power of graphic description could be found united again in the same person. CHAPTER XI. (p. 231) 1840-1850.