His criticism of the objection to the use of a uniform price list for materials, and ignoring the source of supply and the cost of delivery at the point of use, is equally forced, for it admits that "no effort was made to use different unit prices as between counties," and only contends that "in a number of cases" differences in prices were made. The absence of an allowance for interference by labor troubles, weather conditions (which he admits are "a frequent source of annoyance, delay, and sometimes of expense"), Mr. Riggs defends on the ground that it is "an expense difficult to separate and set up," and therefore ought to be covered by an allowance for contingencies. On the same ground, he could easily carry every item of cost of replacement into the contingent account. The two remaining objections specifically raised by the writer are squarely attacked by Mr. Riggs. As to one of them, the propriety of an allowance for carrying charges up to the time of attaining a revenue basis, has been admitted by the Railroad Commission of Wisconsin, but it is a broader question than ought here to be discussed. The writer will only suggest, at present, that in some form or other, these charges must be on the whole and in the long run met out of net operating income, and that the cheapest way, for the user of the services supplied, is to carry them into the capital account—otherwise there must be an early amortization of this item, which cannot do otherwise than to throw a heavy burden on the early schedules of charges. The language of the Wisconsin Railroad Commission on this subject merits quotation, and is as follows:[40]