Then there is money. Restoration and protection of the scheme of things and its adjustment to needful human use, on the scale we are considering in the Potomac Basin, is expensive, often involving many millions of dollars for action against only one phase of deterioration or threat or shortage. In accordance with the breadth of overall aims, much of this money must be Federal. Where benefits or responsibilities are clear, as in relation to sewage treatment plants and sources of water supply, states or communities or institutions usually pay a share. If Federal policies regarding flood protection and river flow augmentation for pollution control are made more logical in the ways sketched earlier in this report--as seems likely--such sharing will increase. Private investment or philanthropy may often play a part, as in the purchase of municipal bonds, the donation of scenic property for public use, or--a hopeful trend of recent date--a private organization's use of its money to facilitate high public purposes. The main example of this last service on the Potomac is the recent purchase and interim retention of important wildlife and park lands on Mason Neck by the Nature Conservancy, for later resale without profit to public agencies when needed authorizations and funds have been obtained. [Illustration] Nevertheless, most such projects do have a public purpose with diffuse benefits, and sooner or later most of their cost has to be paid out of public dollars deriving from collected local, State and Federal taxes. Sometimes it is dispensed through Federal grant programs created by Congress to meet pressing needs, or from other special sources fitting the occasion. More often it must be sought in the standard established manner: concrete proposals for action shaped and presented, with a computation of the cost and the value of expected benefits, to Congress, State legislatures, or local governments for examination and authorization, and funds or bond issues later voted for carrying them out. The cash available for both regular programs and special proposals from year-to-year will vary according to the state of the economy, the number and severity of other demands on government budgets, and their relative apparent urgency. This imposes on planners not only an obligation to make sure that what they propose has public value that fully justifies its price, but also a need to gear immediate priorities and projects realistically to the amount of money there is some hope of getting for them. It is an unhappy fact that there is often less than no point in presenting even fine proposals for legislative consideration at a financially inappropriate point in history. Once defeated, whatever the reason, they may forever languish in limbo.