Rotary Press Method of Impression
Unlike other types of presses where the type was mounted to a flat bed,
the Hoe machine type was fastened to a cylinder and revolved in
  unison with four to ten impression cylinders holding paper.
 The original Hoe Type Revolving Machine operated
with 4 impression cylinders.
In 1854, the introduction of curved stereotype plates made it possible to 
mount whole sheets of type to the central cylinder, as opposed
  to the pieced together type used since the beginning with... 
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