Hollander Beater is a mechanism invented in 17th century Holland to enable the mixing of pulp, and though there are more chemical ways of breaking down materials Hollanders are still commonly used. There are variations of this yet all have an oblong trough with rounded ends in which water and the base material being beated circulate, a rotating cylinder with dull metal blades (known as the roll) and a bed plate of raised dull metal blades in the bottom on the trough.