western boundary of the 76-80 per cent. zone follows the Cincinnati, Hamilton & Dayton, cutting the Baltimore & Ohio and Pennsylvania trunk lines at right angles; and then it jumps across to the east until it strikes the sweep of the Toledo & Ohio Central, which carries it down almost to Columbus. Similarly, the western boundary of the 66-1/2 per cent. zone follows the line of the Pittsburg & Western north from Warren, in order that that line may participate in New York business by working its line north _via_ Painesville on the Lake Shore. Why is it apparently necessary that these zone boundaries should follow along just west of the cross railway lines? The reason may be made clear by a concrete instance. Originally and until about 1891, Louisville, Kentucky, instead of having the 100 per cent. Chicago rate, as at present, enjoyed, on the base of its distance from New York, about 96 or 97 per cent. of the Chicago rate. In other words, the 96-97 per cent. zone shown on our map as interrupted at Indianapolis, partly for reasons already mentioned, originally swept across the map all the way from Grand Rapids to the Ohio river. This territory from Chicago south is served by the Monon Railway (Chicago, Indianapolis & Louisville), whose line, not fully indicated on the map, thus lay partly in 100 per cent., partly in 96 per cent., and partly in 97 per cent. territory. An important part of the traffic of the Monon, as well as of the other independent north and south lines, consists of business coming in from the east at the north and worked south, or coming in from the east at the south and worked north. Or, in other words, this line subsisted in part upon indirectly routed tonnage from New York, let us say, destined for Louisville, but reaching it by way of Chicago junction points. Freight thus hauled around two sides of a triangle, instead of by a direct line, as described in Chapter VIII,[411] constitutes one of the important sources of waste of transportation energy. The Monon by such tactics is able to participate in, and to profit by, a much larger volume of through business. That is to say, its proportion of the entire haul is much greater than it would be if the business moved by the shortest line. Moreover, when indirectly routed, the Monon, often securing for its trunk line connections tonnage for the east which would naturally go to other competitive trunk lines, is able to exact a higher pro-rating than even its extended lateral haul would justify on a strictly distance basis. Such circumstances always greatly enhance the profitableness of lateral hauls to minor connecting roads. It is obvious that much of this transverse haulage would be impossible wherever the lateral railway lines traverse different zones of rates. It might haul traffic from its 100 per cent. end to connect at its 96 per cent. end with a trunk line for the east, but not in the opposite direction. The Monon,