Can a Magazine Live Forever? Scientific American, at 170, Is Giving It a Shot

The oldest continuously published magazine in the United States, Scientific American, is marking its 170th birthday this week — cause for a promotional celebration at its New York offices Wednesday night and also an occasion to look at the title’s secrets to longevity.   To get a little Darwinian, the publication had a strong, sustaining concept from the start, stuck with that idea for the long haul, but also adapted with variations as times changed.