B.

Key to Letfering for Lantern Slides.

Valuable slides may be damaged if left on the screen too long. The Lynhoff Laboratories, Rochester, N. Y., makes a heat-reflecting glass, either clear or diffusing, which may be placed between the slide and the light source in the projector. As a further precaution, irreplaceable slides may be copied in full color at no great expense and with satisfactory results. Cardboard Ready-Mount Kodachrome slides are light and thin. They may be filed 19 to the inch, and are easily packed for mailing. The boxes in which they are returned, 18 to the box, fit well in a 3" x 5" card index file.

A. Chart Reduced to Lantern Slide Size.

1. The original chart wat 6f^" x 9" including margins.

2. The cut from which this illustration

was taken was standard lantern slide size 3Vi" x 4", one-third reduction. The illustration above was reduced Va from that to about the 2" X 2" slide size.

3. Directions on the right of the illustration refer to the dimensions of the original drawing.

Line Width of Letters

Approx. Desig- Width,

nation Sample Line inches

W-1

iV-2 W-2

0.025

0.017 0.017

'^.

/

'W

\,

Ov^^

\v

.:^

/M^;^;

^

j^ritr^

^

Potiiion of Slide Number

Lib«l (Thumb Spot)

Gnd Rulintt Break at Labels and Symbols

Oosed Symbols for Observed Points

Same Source as A Above

C. Suggested Practices for Charts for Lantern Slides.

1. Reduced '/i from oritjinal cut.

2. Cut was reduced from drawing 6 x