The original or master copy for this duplicator is made with a "spirit" hectograph carbon in such a way that a reverse or negative impression is made. This master copy is inserted in the drum. While proceeding through the machine the copy paper is moistened with a thin film of an alcoholic duplicating fluid. When this inserted copy paper is brought in contact with the negative impression of the master copy, it dissolves sufficient dye to produce a copy. This process will make from 200 to 300 clear copies from one original.

2. Type of copy may be printing, handwriting, or typewriting.

3. The master copy can be stored and reused if less than the maximum number of copies

is made from the original. The life of the master copy is from ten to fifteen years.

METHODS OF REPRODUCING

A. Mimeoscope for Illuminated Drawing Board.

1. With the aid of the Mimeoscope and

•tyli, both straight and curved lines, either broken or soHd. are obtainable. Thus, ruled forms specially designed to suit current needs can be quickly and economically produced on the Mimeograph duplicator.

2. Triangle guides, beam compasses, and

circle guides, manufactured especially for the preparation of Mimeograph stencils, are also available.

A. B. Dirk Company, Chicago.

Lithoprint Company of New York. Inc.

B. Two Steps in the Lithoprint Process.

The lithoprint process is a simplified form of lithography. A plate coated with special composition replaces the lithographer's stone and the copy is obtained by a simple process of contact printing. Lithoprint reproductions duplicate the original drawings.