History of the Typewriter

— 39 — Fig. 27 strikes against the face of the several types the instant they are brought within its range, a sheet of carbonized paper, held in contact with a sheet of writing paper, being suspended between the hammer and the type-wheel. Transparent transfer paper may be also employed as well to enable the operator to see the progress of the writing as to preserve a copy. The hammer is operated by an oscillating bar, A, with which it is connected by a small rod, N, hinged to its butt. This rod has on its lower end a catch, which engages an arm projecting from the oscillating bar, A, and, having an eccentric movement, it causes it to act in a manner somewhat analogous to the hopper of a piano. The depression of a key lowers this eccentric arm, and retracts the rod of the hammer. Just as the key has been carried through to its full movement, and the corresponding type brought to a proper position, the catch is pushed off the eccentric and the hammer is impelled against the type by a spring, 0. When the key is released the arm of the oscillating bar engages the catch, and the hammer is ready for a new stroke. It is, however, neces- sary by this arrangement to release one key before striking another ; and it is this necessity that limits the rapidity of the instrument, which otherwise might have struck of' printed characters as fast as the piano can yield consecutive notes. “ Third, now for the feed of the paper. A square open frame, P, which for distinction may be termed the page- frame, slides in vertical grooves formed in the upright part of the case, in the plane of the type-wheel. Within this,