To be worth one’s wages; a good employee. This term alludes to the practice of paying Roman soldiers with rations of salt and other valuable and essential items, whence the Latin word salarium (in turn the English salary), or “salt money.” The term was picked up by numerous nineteenth-century writers. Robert Louis Stevenson used it in Treasure Island (1883): “It was plain from every line of his body that our new hand was worth his salt.”