He contributed frequently to the columns of various literary, scientific, historical, and ecclesiastical serials.
Besides historical works, he left some unpublished manuscript volumes on theology, which show great originality of thought and deep research. He also devoted some pages to the vindication of Cromwell. To his marriage with a lineal descendant of the Lord Protector may be attributed some of the interest he evinced on this subject.
In 1814, Mr. Watson was elected cashier of the Bank of Germantown, which position he held till 1847, when he was chosen treasurer and secretary of the Philadelphia, Germantown and Norristown Railroad Company.
During his connection with the Bank of Germantown he resided in the stone bank building of which the celebrated annalist himself says, “The house in which I now reside was once honoured with the presence of Generals Washington, Knox and Greene, shortly after the battle of Germantown. They slept in it one or two nights.”
In 1859, being at that time eighty years of age, he retired from all active business.
In 1820, he began to collect antiquarian material, the first being history and legends of Germantown, though none of them were printed until about 1828, when some extracts from his manuscript books were printed in Hazard’s “Register of Pennsylvania.”
In 1830 the first edition of the “Annals of Philadelphia,[Philadelphia,]” was issued, the same “being a Collection of Memoirs, Anecdotes, and Incidents of the City and its Inhabitants from the days of the Pilgrim Fathers; also Olden Time Researches and Reminiscences of New York City in 1828.” It was in one volume of eight hundred pages, and illustrated by lithographs.
In 1842 the work was republished in two volumes, revised and enlarged, and again, in 1856, he made a full and final revision, adding an appendix to the second volume. The editions subsequent to the first did not contain the matter relative to New York.
A noteworthy characteristic of Watson was his reverence for the graves of great and good men, who had been useful in their generation, as illustrated in the removal of the remains of Thomas Godfrey, the inventor of the quadrant, and family from a neglected spot on his old farm to Laurel Hill, where a suitable monument was erected by subscription to his memory.
In 1832, he published “Historic Tales of Olden Time” of New York City, which was followed the next year by “Historic Tales of Olden Time, concerning the Early Settlement and Progress of Philadelphia and Pennsylvania.”