The causes leading to the adoption of a systematic rate scheme by the trunk lines acting jointly[390] can be understood only in the light of the conditions existing about 1875. The Baltimore & Ohio Railroad had entered Chicago in 1874, after which time the most furious rate wars between the four trunk lines had been in progress. The main dependence of all these lines was still upon the grain traffic, and all of this was moving in one direction toward the seaboard. As late as 1882, seventy-three per cent. of the trunk line tonnage east bound consisted of such commodities.[391] Moreover,--and this is a point of especial importance,--the bulk of this grain originated in the territory east of the Mississippi and south of Chicago. Over four-fifths of the eastbound traffic came from the states of Illinois, Indiana, Ohio, Michigan, and Pennsylvania. The great northwest and trans-Mississippi territory was not yet opened up. Wisconsin and Iowa contributed only about ten per cent. of the eastbound tonnage, while over two-thirds of the westbound business did not pass beyond Illinois.[392] Nor was the traffic concentrated as yet in the larger cities. Mr. Fink makes it clear that most of the business was gathered up by the trunk lines and their connections from small towns along the way. The modern problem of the great city in competition with the small towns was as yet unknown. The trunk lines had few feeders. Only the main stems to Chicago had been built. Consequently these central states were served by a host of little cross lines, built as local enterprises, many of them radiating from Chicago, Cincinnati, Toledo, or Cleveland at right angles with the trunk lines, and, for the main part, engaged in an endeavor to open up their territories to water communication with the East by way of the lakes and the Erie Canal. Rail rates, nominally at least, were still high, the rate first-class Chicago to New York, for example, being about double its present figure; and the conditions of railway operation were such that water competition was a matter for grave concern. Every change in the lake situation was at once reflected in the rail rates, violent dislocations at the opening and closing of navigation in the spring and fall being of especial importance.