"Only within the last few years have the American public, the Government and the American oil companies appreciated the gravity of the situation that will result from our oil supply becoming so depleted as to be inadequate to meet demands. The situation as regards petroleum is nowise different from that of any other natural resource. When the supply of any resource is plentiful and easily obtainable, little attention is paid to consideration or efficient utilization, but when the supply begins to fail, conservation begins to be applied and possible substitutes are sought."