of customers are estimated approximately twenty-four hours in advance, and a "dispatcher" is employed for the purpose of procuring information from hour to hour with respect to what the needs may be.
At all times there is a supply of gas in the thousand miles of mains. This reserve is estimated to be about fifty million cubic feet; or an amount suffioient to meet requirements for several hours. The mains are "tapped" for diversion purposes, and the pressure is reduced substantially and then "metered" to the customer.
It is true that no particular gas pumped into the lines in Louisiana can be labeled as the identical gas supplied to a designated customer, because the nature of the commodity precludes such identification. We might assume, as an illustration, that appellee's dispatcher, during a stated period of ten minutes, directs that gas be pumped into its line at the Louisiana point of entry under a constant pressure of 150 pounds, and it could be ascertained by mathematical calculations that a designated quantity of gas had been set in motion. The rules of physics and of common sense tell us that the quantity thus ascertained and started on its journey is not necessarily the same gas appellee will bill to a designated customer under a specific contract, nor is there any process known to science by which its identity can be known.
Such gas, and all gas pumped into the mains in Louisiana, becomes part of a supply stored along a thotisand miles of mains. It is affected by heat and cold, and by climatic variations. Expansion and contraction are attributes of its density and function independently of appellee. An individual customer's "tap" line may be idle, or it may be active. A shut-down by the Arkansas Power & Light Company in Little Rock, a change from steam to hydro-electric service, would affect continuity of supply and demand. In these circumstances, transportation of gas theoretically "scheduled" to reach a point in Southern Arkansas one, two, three or four hours after entering the main, would be delayed indefinitely. According to acknowledged principles this
