Page:Graphic methods for presenting facts (1914).djvu/29

 Fig. 6. Conjugal Condition of the Population of the United States in 1900

The four lower bars show components of the total population represented by the upper bar. The combined length of the four lower bars equals the length of the upper bar

Fig. 7. Males of Voting Age in certain States, in 1900, by Color and Nativity and by Illiteracy

A method for two successive divisions into components is shown here. The proportion of illiterates in each group is brought out by the horizontal ruling

is used, all the bars being made of equal width. In this particular case (Fig. 7) we have a total split into its components and again sub-*divided so as to show the prevalence of a second factor which is included in the first. Thus, we see the proportion of illiterates in each of the main groups of population for each State. All of the States are shown on the same basis, since all are depicted by bars of the same length representing 100 per cent. It is not easy to make a clear black-and-white drawing if one kind of cross-hatching must be placed on top of another kind. Fig. 7 shows that it is possible, however, to superimpose two kinds of cross-hatching and get a drawing that is fairly clear. The facts in this chart would have been brought out better if colors had been used for the main divisions of population. Ruled cross-hatching in black to represent the percentages of illit