Hay Rake

It's not the 18th century, probably 19th century but it is an invention. I assume someone in the 18th century probably thought it would be a good idea to find another way than a scythe for raking hay. 
A hay rake may be mechanized, drawn by a tractor or draft animals, or it may be a hand tool. The earliest hay rakes were nothing more than tree branches, but wooden hand rakes with wooden teeth, similar in design to a garden rake but larger, were prevalent in the 19th and early 20th centuries, and still are used in some locations around the world.
Here's a bit more about hay rakes. The color version is an extra, a bit of nice foliage.