Page:Graphic methods for presenting facts (1914).djvu/43

 Fig. 21. Value of Manufactured Products of Principal Cities of the United States in 1909

This chart, taken from a Census office report, would have been greatly improved if the actual figures had been placed at the left of the bars in the manner shown in Fig. 27

It is stated by the author of the book in which Fig. 19 is used that tests have shown that children grasp relative quantities better when separate squares are used than when the information is shown by lines or bars. If this is the case, it is probably due to the fact that the squares appear more prominently to the eye than do the bars, and it would seem that the best kind of presentation might be made by using much wider bars so that the bars would be easily seen. Bars can be made as wide as some of the squares seen in Fig. 19 and, if it seems best, the bars could be made in outline rather than in solid