In Globe Cotton Mills v. National Labor Relations Board, 5 Cir., 103 F.2d 91, 94, the court said: "there is a duty on both sides * * * to enter into discussion with an open and fair mind, and a sincere purpose to find a basis of agreement touching wages and hours and conditions of labor, and if found to embody it in a contract as specific as possible, which shall stand as a mutual guaranty of conduct, and as a guide for the adjustment of grievances."