In an action by a broker against his principal for compensation, plaintiff bears the burden of proving by a preponderance of the evidence that he was employed by defendant to find a purchaser and that he found a responsible one. Hammond v. Mitchell, 61 I11. App. 144; Harrison v. Prestroski, 97 Iowa, 166, 66 N. W. 93; Chilton v. Butler, 1 E. D. Smith, 150; Schatzberg v. Grosworth, 84 N. Y. S. 259; Harrel v. Veath, 13 N. Y. St. 738; Summa v. Dereskiawicz (Conn. Sup. '09), 74 A. 906; Bal-lentine v. Mercer, 130 Mo. App. 605, 109 S. W. 1037; Rice v. Neuman, 115 N. Y. S. 83; Whitehouse v. Gerdis, 145 N. W. 338, 95 Neb. 228; Be Perow v. Groomes, 42 App. D. C. 287; Groves v. Oil Belt Trac. Co., 169 I11. App. 204; Steinman v. Tully, 155 N. Y. Sup. 215; Wheelan v. Hunt, 133 P. 52, 37 Okl. 523; Barrow v. Newton, 48 Pa. Super. Ct. 382; Jackson v. Lacy, 102 A. 584,

92 Conn. 256; Balto. Car Wheel Co. v. Clark, 104 A. 357, - Md. Sup. -; Harris v. Millikan, 208 S. W. 633, - Mo. App. - . Compare Sec. 707.