Morley Adams, Toy-Making at Home: How to Make a Hundred Toys from Odds and Ends
“ Engines of all sorts are always fascinating to boys and girls, and later on we shall describe some excellent ones. At this point we wish to describe what is possibly one of the simplest forms of engine known, and certainly one of the earliest. It is the engine driven by a flanged wheel, which itself is made to turn by the weight of something falling on the flanges. The commonest form of this wheel is the water wheel, where the weight of the water falling on the wheel causes the revolution. ”
