Assuming the reasonableness of a difference in charges between carload and small shipments, where shall the dividing line as to size be drawn? This is the important and perplexing problem of minimum carload rates. Turning to our excerpt from the Western Classification on page 298, it appears that 24,000 pounds of advertising matter, N. O. S. (not otherwise specified), must be shipped at one time in order to warrant a carload rate. Under such circumstances a consignment of 20,000 pounds would be classified first instead of third class--the difference in rate varying according to distance, but in all cases being substantial. Between St. Louis and St. Joseph, Missouri, for example, the charge would be sixty instead of thirty-five cents per hundredweight. Were the minimum weight for carloads but 15,000 pounds, as in the case of harvesters under the Southern Classification, this particular shipment of advertising matter would have enjoyed the full benefit of wholesale charges.[365] From this instance it is apparent that the point at which the minimum carload weight falls, is of great importance in the determination of the actual rate--an importance also dependent, of course, upon the spread between carload and less-than-carload charges. It is also evident that minimum carload ratings may readily be used as a means of advancing charges. If, as appeared in a recent case,[366] the minimum carload for wool in sacks was advanced between 1896 and 1912 from 15,000 to 20,000 pounds, the effect upon the shipper of a consignment of 18,000 pounds, for example, would be as truly an increase of charges as if the freight rates themselves had been actually advanced. For under the new schedule, he would be compelled to pay less-than-carload charges instead of the lower carload rates formerly granted. Moreover, it is apparent that minimum carload weights may enter seriously into commercial competition in a number of ways. If 45,000 pounds of raw cotton by a special round-bale process can be loaded upon a standard car; when but 25,000 pounds of the ordinary square bales could be carried by the same equipment; it is evident that tariffs based upon the higher minimum would especially favor one set of competitors as against another.[367] They might, in fact, be sufficient to turn the scale entirely in favor of the round-bale system throughout the South. Granted, however, that such heavy loading makes for economy in operation, it is clear, nevertheless, that the carload minima must be so established as not to discriminate against the great bulk of shipments of the more common sort. All along the line one meets with such illustrations of the bearing of the minimum carload upon rivalry in business. Large shippers are continually striving for a high minimum. The small shippers oppose it for the same reasons. In a similar way the interest of the manufacturer distributing his goods direct, in competition with middlemen, is vitally affected.[368]