to the average
cost of services to traffic in the same group. For in the first place
the cost of the service cannot be ascertained. And secondly, if it could
be ascertained, it would be of no use as a standard. To charge the
average cost would be to drive away a large portion of the traffic and
so increase almost proportionately the average cost of the remainder.
This increase would then drive away a fresh portion, and so once more
increase proportionately the cost to that still remaining. And so
on."--W. M. Acworth, "The Theory of Railway Rates," _Economic Journal_,
London, 1897, p. 324.

[646] "The process is in practice worked out as follows. First comes
classification. The whole of the commodities known to commerce are
entered on a list divided into classes, eight in number here, six in
France, and about ten in number in the United States. To each class
belongs a normal scale of rates, ranging, let us say, from 3/4d. per
mile in the lowest to 4d. per mile in the highest. The classification
undoubtedly takes account of greater or less cost of carriage to the
companies, arising out of the differences of packing, liability to theft
or damage, proportion of space occupied to weight, etc. But it is safe
to say that its main principle is, the more valuable the commodity, the
higher the rate it can afford to pay."--Ibid., p. 325.

[647] "Historically this theory has been recognized and approved by
English legislation from the time when Adam Smith applauded the equity
of statutory turnpike tolls at the rate of one shilling for a light
carriage and eightpence for a heavy dray, through the whole long series
of Canal Acts and Railway Acts, down to the elaborately careful revision
of the railway companies' charging powers in the series of Provisional
Order Confirmation Acts dated 1891 and 1892. The opinion of modern
economists all over the world as to the justice of the underlying
principle may be conveniently summarized in a sentence borrowed from the
first annual report of the American Interstate Commerce Commission:
'With this method of arranging tariffs little fault is found, and
perhaps none at all by persons who consider the subject from the
standpoint of public interest.'"--Ibid., p. 317.

[648] "One great element of the reform introduced by you in the postage
was, that there should be one uniform rate throughout?--Yes, it was
proposed with a view to simplification, but the principle has been
carried to an extent tha