I’m fascinated by English idioms. Did you know that “sweating like a pig” isn’t referring to an animal but to “pig iron,” an iron ore, as it cools? This Smithsonian article discusses some other idioms, like “once in a blue moon,” but I’d like to know if YOU have the background scoop on any idioms not listed in the article: http://blogs.smithsonianmag.com/science/2013/05/once-in-a-blue-moon-and-other-idioms-that-dont-make-scientific-sense/?utm_source=smithsoniantopic&utm_medium=email&utm_campaign=20130526-Weekender