JOHN A. Fleming, while employed as a hard rock miner, received injuries, the results of two accidents, one on May 2, 1925, the other on December 29, 1931. The first occurred while he was employed by Oston Company and United Gold Mines Company, which were insured in the United States Fidelity and Guaranty Company. These are plaintiffs in error, and the companies may sometimes herein be referred to as "first employers." The second accident occurred while Fleming was in the employ of the Cresson Gold Mining and Milling Company, insured by State Compensation Insurance Fund. Both are defendants in error, the company being herein designated as "second employer." Fleming will be referred to as claimant.