Although no key accompanied this chart, according to another map in the same pamphlet, the dots represent population. The numerical value of each dot was not given.

2. The important feature about this map is the use of color to emphasize the circle around

Toronto.

DOT AND PIN MAPS

U. S. Department of Af(riculturr. Bureau of Aftricultural Economics.

Number of Slaves In the United States In 1790 and In I860. 1. These two maps are the first and last of a group of six. Space does not allow all six

to be shown here.

2. The use of these two maps in a history lesson would clarify and simplify the slave

problem of 1860. This material in tabulated or verbal form would be formidable.

3. Only a section of each map is reproduced here.

GRAPHIC PRESENTATION

Brll Telephone Laboratories. Inc., New York City.

A. Exhibit of the Bell System at the New York World's Fair, 1939.

Brinton, "Graphic Mclhodi," McGraw-Hill, 1014.

B. Residence of the Men of the Class of 1907, Harvard University, Six Years After Graduation. The Bead Wire for Boston Includes All Men Living Within Twenty-five miles of the City Hall.

1. Rather than have a pin for each individual stuck in the map around the city in which

he Hved, a bead was put on a wire for each person in the same city.

2. Every tenth bead on a wire is white to aid in counting the beads.

DOT AND PIN MAPS

Series 1 500 I