I really can't think of anything else that wouldn't quickly give it away, so here is the final clue I can come up with. This picture, taken circa 1915, is also in the collection.
Best
Rob
Abraham Lincoln is the only man, dead or alive, with whom I could have spent five years without one hour of boredom.
--Ida M. Tarbell
I want the respect of intelligent men, but I will choose for myself the intelligent.