This was a bit of fun. It's from an early 18th century scientific coursebook. Bookselling and publishing were very closely linked at the time. I would guess that the Author had had run-ins with the book trade on previous occasions.
"Whereas some Booksellers have declared, that as soon as my Course comes out, they will get it translated into French (as cheap as they can, no doubt) lest my Book should be spoil'd by an hasty, and perhaps ignorant Translator, I intend to translate it my self, having already done more than half; and if any other Translation appears, I shall write my Name in each Book with my own Hand, that my foreign Auditors may not be imposed upon."