So, I hit the link expecting to be underwhelmed, when the following language leapt off the page:
Now it came to pass, in the one thousand eight hundred and twelfth year of the christian era, and in the thirty and sixth year after the people of the provinces of Columbia had declared themselves a free and independent nation;
2. That in the sixth month of the same year, on the first day of the month, the chief Governor, whom the people had chosen to rule over the land of Columbia;
3. Even James, whose sir-name was Madison, delivered a written paper to the Great Sannhedrim of the people, who were assembled together.
4. And the name of the city where the people were gathered together was called after the name of the chief captain of the land of Columbia, whose fame extendeth to the uttermost parts of the earth; albeit, he had slept with his fathers.
I was stunned.
The book is The History of the Late War between the United States and Great Britain by Gilbert J. Hunt. It was published in 1816. Its author lived in New York City, and, according to the person who posted the original link, it was "widely available in New York schools in the 1820s."
Thus far I have only read the first two chapters, but I have to say that the resemblance to the language of the Book of Mormon is very striking. Whoever discovered this may have unlocked an important aspect of the mystery of the production of the Book of Mormon.
Take a look for yourselves: