This is an interesting overview of the tricks salesmen used to cheat their customers. By using containers with false bottoms, they created the illusion that there was more product than there really was.
TRICKS OF THE SHORT WEIGHT AND SHORT MEASURE MEN: Comm’r. Driscoll Wages War on Hucksters and Dealers Who Cheat in Their Sale of Foodstuffs (PDF)
From July 17, 1910