The period outside the quotation marks is not a copy error. For at least two centuries, it has been standard practice in the United States to place commas and periods inside of quotation marks.
A: The cotton gin was invented by Eli Whitney in 1794. It revolutionized the cotton industry in the United States but became a controversial invention as it b... Full Answer >
Document Description: This obituary for Eli Whitney praised the mechanical ingennuity of the man largely credited with inventing the cotton gin. Even after Eli Whitney patented his machine, there were other mechanics and inventors that made their own versions of the gin. Whitney never became rich from his invention.