Figures purporting to show the aggregate by which the investors of the United States have enabled this country to become the dominant factor in world production must be considered in light of the fact that such totals are in a large measure merely estimates. It is not possible to obtain detailed statistics covering the cost of drilling that has gone for naught; but an approximately accurate estimate can be reached by striking an average based on the experience of leading companies. It is fair to estimate production at $1,000 per barrel of daily yield, multiplied by the current price for that grade of crude. On this basis Oklahoma leads all other fields with production valued at $958,517,000. The fields in north and central Texas are worth on this basis $617,690,000 while California is third with a total of $456,443,000. On the basis of the country’s production in February, 1920, California produced almost exactly the amount of crude derived from Oklahoma, 274,966 barrels per day, in the one case, as against 273,862 in the other, but the posted price of Oklahoma crude was $3.50 per barrel as compared with $1.66 for the lower grade California product. The daily average production in February, taking the country as a whole, was 1,130,759 barrels, and the value of that oil at the current price was $3,541,511. This would give an approximate valuation of the country’s production, on the basis assumed, of $3,541,511,000. Discovery of a new pool means a race to lay pipe-lines in the field to relieve the temporary storage tanks which are generally of limited capacity. Oftentimes, a considerable investment made in anticipation of large production is rendered almost valueless by the early exhaustion of new wells or by their failure to maintain anything like their flush production. These lines in the different fields are known as gathering pipe-lines. They are connected with main trunk pipe-lines running to the various refining centres. According to the Bureau of Mines, there are at this time approximately thirty-two thousand miles of trunk pipe-lines and eleven thousand five hundred miles of gathering lines. At the present day replacement cost, this mileage is worth, respectively, $360,000,000 and $40,000,000, a total of $400,000,000. The money actually invested for the existing pipe-lines is probably considerably less than this sum by reason of the fact that a great deal of mileage was built prior to the present era of high costs, but it is a safe assumption that the pipe line system represents an actual investment of not less than $300,000,000.