On December 6, 1811, the most destructive earthquake of the century occurred in the country bordering on the lower Ohio River, and on the Mississippi, completely changing the course of the two streams at numerous points. Cramer promptly published a notice of the fact, warning navigators of the danger, and requested newspaper editors to print his notice.[281] The corrections were then made in the next edition of the _Navigator_ which was published in 1814. The success of the _Navigator_ reached its climax in 1814, when it contained three hundred and sixty pages. From that time the size of the book gradually decreased, until in 1824, when its publication was suspended, it had fallen to two hundred and seventy-five pages. The information relating to Pittsburgh, and to the rivers flowing by and below it, cost Cramer infinite pains to collect. From Cramer’s _Navigators_ the early travelers and later historians drew for facts when writing about the Western country, often without giving credit. Cramer complained of the piracy. In this connection he mentioned the Rev. Thaddeus Mason Harris, whose _Journal of a Tour_ was published in Boston in 1805. He was especially bitter against Thomas Ash, the writer of a book of travel which appeared in London in 1808. He accused Ash of having taken his account of the Allegheny, Monongahela, and Ohio rivers verbatim from the _Navigator_ for 1806.[282] Notwithstanding this charge, Ash’s book must have had some merit in Cramer’s eyes, as he republished it the same year that it came out in London. Most of the writers, however, who obtained their information from the _Navigator_, gave it as their authority. John Mellish who was in Pittsburgh in 1811, commended the work: “The Pittsburgh _Navigator_ is a little book containing a vast variety of information regarding the Western country, the prosperity of which seems to be an object of peculiar solicitude with the editors.”[283] Christian Schultz, coming through Pittsburgh in September, 1807, had this to say: “Before I left Pittsburgh I purchased the _Navigator_, a kind of _Blunt_, or _Hamilton Moore_, for these waters; it is a small pamphlet, but contains a great deal of useful and miscellaneous information, and is particularly serviceable to a stranger.”[284] _Blunt_ was the _American Coast Pilot_, published in 1796 by Edmund Blunt, and still used in recent years; _Hamilton Moore_ was an English work called the _Practical Navigator_, of which many editions were published in London by Hamilton Moore. REFERENCES CHAPTER VIII [271] _The Western Gleaner or Repository for Arts, Sciences, and Literature_, Pittsburgh, Pa., August, 1814, vol. ii, pp. 173–175. [272] _Pittsburgh Gazette_, June 28, 1800. [273] _Pittsburgh Gazette_, December 4, 1801. [274] _Tree of Liberty_, October 18, 1800. [275] _Pittsburgh Gazette_, March 20, 1801. [276] _Tree of Liberty_, June 13, 1801. [277] _Pittsburgh Gazette_, December 4, 1801. [278] _Tree of Liberty_, August 7, 1802.