In the Perelman-Gunning dialogue, it would be useful to distinguish long-run average costs (LAC) from short-run (SAC). Starting with excess capacity, SAC fall as demand rises, but then rise after a minimum point. That is the simplest notion of economies to scale, the Hotelling's Bridge case. However, there are often falling LAC in having more capacity, as with larger pipes or aqueducts, larger buildings, wider highways, higher dams, etc. Here, the investment decision becomes a trade-off between the cost of carrying excess capacity during the early years, and the cost of twinning a facility later on. It makes a great problem for students of investment theory. Many factors interfere with optimal economic decisions in such cases. One, worthy of much more attention, is rent-seeking. Wicksell called attention to premature establishment of suburban retail branches, to establish a local monopoly, or nail down territory for future exploitation. Utility extensions into lean, subeconomic territory secure a more permanent monopoly. Railroads under the U.S. and Canadian land-grant systems were an egregious case. Water supply in the Western States, with their doctrine of prior appropriation, are an extreme case. Here, money and real capital are "invested" for the sole purpose of acquiring natural resources, with no social capital created at all. Other examples are legion, once one catches on to the basic idea. Mason Gaffney