William O. Douglas,
Colorado Interstate Gas Company v…
“ If Congress had prescribed a formula it would be the duty of the Commission to follow it. But we cannot say that under the Natural Gas Act the Commission can employ only one allocation formula and that that formula must entail a segregation of property. A separation of properties is merely a step in the determination of costs properly allocable to the various classes of services rendered by a utility. But where as here several classes of services have a common use of the same property difficulties of separation are obvious. Allocation of costs is not a matter for the slide-rule. ”
