The message on the back of this postcard was written 115 years ago today — Oct. 5, 1910. The date on the postmark is unreadable, other than the year 1910, but the sender of the card dated the message in pencil. The card shows Duluth’s Board of Trade building, which still stands at 301-307 W. First St., now an 84-unit apartment building branded as Duluth Board of Trade Lofts. …