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Rh observed reap the benefit in increased output, because less work is spoiled by bad register, and less time is spent in getting work to register. Even with the regulation of atmosphere suggested by the use of the dry and wet bulb thermometers or hygrometer, the paper must be matured in the machine-room, that is, the paper must be exposed in order to allow it to absorb moisture if too dry, and to part with moisture if too damp, so that the paper may be as stable as possible while the condition of the machine-room remains constant. It is important that the amount of atmospheric moisture should remain constant, and printers'

engineers will advise on the means of attaining this end.

Various methods may be adopted for suspending paper. In some cases the paper is hung over lines, about a quire at a time, exposed to the atmosphere and dust of the machine-room. Hanging frames are supplied by vendors of printers' supplies, in which the paper is clipped by a ball or swinging lever, and about a quire is held in each of the clips, a perpendicular position minimising the danger of dirt. By use of these frames a large quantity of paper can be treated in a comparatively small space. The "Swift" machine is another method of maturing