I've noticed a small difference between this scanned version and the text version that is online at:
http//www.heraldmag.org/olb/contents/russell/z81sep.pdf
On page 120 in this scan version, Russell references the book Day Dawn for additional information about chronology supporting 1874.
*The chronology, time proofs, etc., can be had in a book entitled "Day Dawn."
Address, A. D. Jones, Pittsburgh, Pa.
The online text version (page 95 of the PDF) instead says:
*The Chronology, time proofs, etc., can be had in a book
entitled "Millennial Day Dawn," soon to be published from this
office.
I'm guessing that earlier editions have the reference to Day Dawn by Paton and later editions of Food For Thinking Christians might have changed this due to the falling out Russell and Paton had. Also, Paton planned on publishing a new edition of Day Dawn which reflected his changed teachings.