TRUNK LINES. 1870--1889 Chicago and Northwestern Chicago, Milwaukee and St. Paul Chicago, Rock Island and Pacific =Av. of 6 Lines West of Chicago= Chicago, Burlington and Quincy Illinois Central Chicago and Alton Boston and Albany Michigan Central New York Central =Av. of 7 Lines East of Chicago= Pennsylvania Lake Shore and Michigan Southern New York, Lake Erie and Western Pittsburgh, Fort Wayne and Chicago =Explanatory.=--The upper edge of the deep shade marks the fluctuations of the average rate charged by the seven lines east of Chicago.--The upper edge of the light shade marks the fluctuations of the average rate charged by the six lines west of Chicago.--Each particular road has a distinctive line, which makes it easy to trace it among other lines.--All Western lines are accompanied by lines of color, to distinguish them plainly from the Eastern lines, and to make their relation to their own average more easily discovered. The Boston and Albany is the only Eastern line whose rate places it near the Western lines, but the absence of color prevents it from being taken for a Western line, which it might otherwise be, especially during the last three years, in its journey through and above them all.--The C. B. & Q. Road makes no report later than 1879.--The Chicago and Alton report begins at 1874. =Explanatory.=--The diagram upon which the rates are charted (like all such diagrams) is constructed of perpendicular and horizontal lines. Each line, and each space between lines, has a particular meaning. The perpendicular spaces represent years, indicated by the figures at the top of each space. The horizontal spaces represent money values, each space representing .2c (two mills). Each horizontal line represents a particular money value, marked by the figures at the end of the line. Each black dot represents the average annual rate of some particular road. For example, take the Boston and Albany Road. Starting with the name and following the tracing line, the 1870 dot is found just below the 2.2c (2 cents and 2 mills) line. This indicates that the average rate charged by that road in 1870 was a trifle less than 2.2c. Following the line leading from the 1870 dot into the 1871 space, the 1871 dot is found a little below the center of the space between the 2c line and the 2.2c line, indicating a rate of a little less than 2 cents and 1 mill for 1871. The next year it is lower still. In this way the history of any road is quickly traced.] _Largest Receipts._--A comparison on the basis of gross receipts gives the best means of judging of the financial importance of the several roads, for it measures the volume of business done. On page 435 is given such a comparison of the fifteen roads (of the twenty-two referred to above) reporting the largest gross receipts.