The advantage of the graph plan in this instance is that it shows an obvious inconsistency by pictorially contrasting the rate of one class with that of another. In all properly adjusted scales of rates there should be a definite relationship between the rates of the lower classes and those of the first class, or whatever rate is chosen as the basis.

Method of Construction

The four steps necessary in constructing a twodimension graph are indicated in Fig. 43. In determining the lines, or curves, as they are commonly called, Step 1

Step 2

dots may be inserted first in the proper square; when all the dots indicating the rates have been definitely indicated, they may be connected with lines, as in the figure.

Fig. 44 indicates a chart which was prepared as an exhibit in the case of the Atlas Portland Cement Company v. the Boston & Maine Railroad, comparing the present cement rates on the Boston & Maine with cement rates on the New York Central and on the Delaware & Hudson, and with the constructive rates on the basis of minimum shipments of 50,000 and 72,000 pounds, respectively.

The horizontal and vertical line method may also be used to indicate the topography of a given section of the country, or the elevation of various points in and near a city, as shown in Fig. 45. Here the marginal numbers represent the elevation in feet, while the figures at the top represent the distance of the destinations from the starting point.

BAR CHARTS

In a bar chart, the full length of the bar or block represents 100 per cent, and the various elements which go to make up the total are indicated by subdivisions of the bar.

If it is desired to depict the inbound and outbound tonnage of an industrial shipping concern, and if the figures obtainable indicate that the ratio is 45 per cent inbound and 55 per cent outbound, on a bar chart this would be indicated as shown in Fig. 46. If it were desired to distinguish between different classes of traffic, say, for example, between carloads and less

LROY

than carloads, the graph could be so modified as to include this information, as illustrated in Fig. 47.

ODURHAM

TO GLAZEER PARK

OTALBOT

LUBES

BASHLOW

A 45-A Two-Dimension Graph Applied to Topography

Aar or block chart is sometimes used in making rison between one commodity and another.

Thus the distances such commodities may be transported for given sums are shown in Fig. 48.

Perhaps this type of chart is employed most effectively to compare period performances with respect to tonnage. Fig. 49 is a chart used for this purpose. The numbers at the top of the sheet are those of the tons handled. At the end of each month a block is inserted showing the amount of work done, and, if desired, dotted lines or bright spaces may be utilized,

as shown, to indicate the preceding year's performance for the same period.

SUPPLY AND DISTRIBUTION CHARTS

Supply and distribution charts are useful in making plans for the growth or readjustment of a concern's shipping activities. Sometimes they are used to picture how the traffic resources of a region correspond to production and consumption. Fig. 50 is a chart of