Publication by this film method is also coming into use for research material which does not require a large edition. The economy and convenience of this can easily be seen. The use of Microcolor film by Bibliofilm Service adds to the scope and value of research extract copying, since colored specimens and objects as well as illustrations may be reproduced and used either for individual reading or projected on a wall screen for class or lecture use.

REFERENCES:

Morgan. Willard D., and Henry M. Lester, The Leica Manual, Morgan & Lester, New York City, 1937.

1. For reading books or records

graphed on 35 mm. film.

2. Turning the handle changes the pages

either backward or forward.

3. The image is magnified 12 diameters.

4. The Reader may also be used as a

projector for ordinary screen.

5. It may also be used as an enlarging

printer, making enlarged paper print copies of any microfilm material.

Chapter 48 PREPARATION OF ILLUSTRATIONS

THE preceding chapters have shown the many ways in which information may be presented in graphic chart form as well as information on how to read a graphic chart. Choice of the form in which material will be best presented, while an important step, is not always the first or last step. The following chapters will show

Bausch 6t Lomb Optical Co., Rochester, N. Y.

A Reducing Glass.

1. The diameter of this glass is three inches. It will reduce in the ratio of about two to

one. The reducing glass is made with a double concave lens of white ophthalmic glass, protected by a wide chromium rim.