A Simple Multiplier
Write on a card or strong paper the letters, figures, etc., which you want to reproduce. Then all along the lines or tracing, with a needle, prick holes in close proximity at equal distances.
Place the sheet so prepared on a pad made of several sheets of blotting paper, smeared with blue analine ink, or a mixture of lamp-black and oil.
Fix the corners with tacks or drawing pins, and draw your copies by simply placing the blank sheets over the pricked one, and press them down. The words, figures or designs will be reproduced in dotted lines if the holes have been well pricked. In this way a good number of copies can be drawn.