=261. Mimeograph and Multigraph.= The mimeograph (Fig. 148) is a more complicated device for reproducing duplicates than the hectograph, but more copies may be made at faster speed on this machine and the stencils may be saved for making more copies later. A stencil (tissue paper, usually blue, fastened to a sheet of equal size waxed cardboard) is cut by a typewriter. This is done by removing the ribbon and allowing only the outline of the type to cut thru the tissue which has been saturated with "Dermax," a liquid wax which is brushed over the surface of the waxed paper, and the tissue paper carefully smoothed out upon it. Some stencil paper or waxed sheets do not require this treatment of "Dermax"; instead a tissue or silk sheet is placed under the stencil paper. When the desired wording is cut, the cardboard is torn off at the perforated line, leaving the four holes which attach the stencil to the roller of the mimeograph machine. First see that the pad on the machine is well inked, and then fasten the stencil to the pins at the top of the roller and with bar at the bottom, seeing that it is smooth. [Illustration: FIG. 148. Mimeograph.] Set the adjustment which indicates the number of copies turned out, so that it is not necessary to count them while printing. (Full directions are printed on this adjustment.) Place the paper on the feed board, far enough down for the sheets to come in contact with the rollers which feed them in, and turn the handle. If the proportion of space at top is greater or less than desired, set the attachment for regulating the space. Full directions are printed on each attachment of most machines. See that the ink tank which is located inside the cylinder is kept full of the best ink. Ink the pad by pushing the brush across the inside of the perforated cylinder. Multigraphs differ from mimeographs in that they print the copy from type instead of thru a stencil. The type is set in a cylinder that is covered by an inked ribbon. Manuscripts printed by a multigraph look more like typewriting than those printed by a mimeograph. When turning out less than a thousand copies, the mimeograph will be found more economical on account of the small amount of time required in preparing the stencil. QUESTIONS FOR PART IX 1. By what means are dumbwaiters operated? 2. Can you see any relation between the construction of door stops and force pumps? 3. What is the power for rolling up a window shade? 4. What does lock-stitch look like? How does chain-stitch differ from lock-stitch? 5. In what way do lock-stitch machines differ from chain-stitch machines? 6. What are the advantages of each? What are the disadvantages? 7. What is the tension? How is it adjusted? How is the length of stitch adjusted? 9. In what ways is an automobile engine like the gasoline engine and the electric motor used in rural homes for operating household machinery?