In Board of Trade v. Christie Grain & Stock Co., 198 U.S. 236 (1905), the court said: "We must suppose that from the beginning, as now, if a member had a contract with another member to buy a certain amount of wheat at a certain time, and another to sell the same amount at the same time, it would be deemed unnecessary to exchange warehouse receipts. We must suppose that then as now, a settlement would be made by the payment of differences, after the analogy of a clearing house. This naturally would take place no less that the contracts were made in good faith, for actual delivery, since the result of actual delivery would be to leave the parties just where they were before. Set-off has all the effects of delivery."