Note the scale duceS rOU^hlv thirtv times at the top of the chart ' & J ' J

as much cotton as Brazil. Bars in one dimension only would show the comparison accuratelv. Under any circumstances, the use of the squares of Fig. 19 with the center line through the centers of the squares gives an extremely poor arrangement.

SIMPLE COMPARISONS

VAtira OF PBODtTCTS FOB PBINCIPAL CITIES: 1909.

CITIES

NEW YORK

CHICAGO

PHILADELPHIA

ST. LOUIS

CLEVELAND

DETROIT

PITTSBURG

BOSTON

BUFFALO

MILWAUKEE

NEWARK

CINCINNATI

BALTIMORE

MINNEAPOLIS

KAWSAS CITV. KANS.

SAN FRANCISCO

JERSEY CITV

IND1ANAPOLI3

PROVIDENCE

nOCNESTER

LOUISVILLE

SOUTH OMAHA

VOUNOSTbWN

LAWRENCE

NEW ORLEANS

WORCESTER

BAVONNE

AKRON

PERTH AMBOY

LYNN

PATERSON

LOS ANGELES

BRIDGEPORT

FALL RIVER

PEORIA.

TOLEDO

OMAHA

DAYTON

LOWELL

VONKERS

ST. PAUL

KAN8AS CrTY. MO.

NEW BEDFORD

DENVER

READING

NEW HAVEN

SEATTLE

WATERBUnV

HUNDREDS OF MILLIONS

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, thie bars could be made in outline rather than in solid