B, A Comparison of the Number of Tractors Per One Thousand Farm Families in Three Groups of Farmers in the United States.

1. The "heart" referred to in this chart means a group of states that form the heart of the

farming industry, as estimated by the Meredith Publishing Company.

2. The date to which this comparison applies is not definite: the sources listed for the

information given were dated 1930 and 1935.

GRAPHIC PRESENTATION

-ooo I4.59I.OOO •*" ONE MILE

32.837,000 ONE MILE

TT'TT'TT'TT'TT'7T'7t'7T"7T'7T'7T'7TTT7T7T"7v'7^'Tr

Brinton. "Graphic Methods," McGraw-Hill, 1914.

SCALE .9

A. Comparison of fhe Average Number of Passengers Carried Per Mile on United States Railroads in 1899 and 1911.

1. The theory behind pictorial unit bar charts is that there are more or less units rather

than larger or smaller units. A pictorial unit bar chart consists of rows of symbols rather than large and small symbols.

2. In this chart, each figure represents 2000 passengers.

NOPOmCdAISED

6.128 LBS OF POWC HAISED

ni6 _ =.==„„^

IZm LBS OF POR.K. RAISED

From "HumanizifiK the Greater City'i Charity" by Bertrand Brown, Department of Public Charitie*, City of New York, 1917.

B. Increase in Poric Production at the Sea View Farms fThe New York City Farin Colony) from 1913 to 1916.

Apparently the basis on which the pigs were placed inside the fences was this: one pig was added for each 6000 pounds of pork raised.

CHARACTERISTICS OF PICTORIAL UNIT BAR CHARTS:

1. They are effective for popular presentation of educational matter.