Walk into a Walmart, Target, any drugstore chain in your neighborhood or a corner bodega for New York City dwellers, and chances are you’ll find an Ivory Soap bar, or a pack of 10 bars for under ...

A bar of soap, invented almost 150 years ago and still selling in stores today, has become a part of Americana largely by advertising its two strange merits: It floats and its “99+44⁄100% Pure.” ...