Section, act May 9, 1938, ch. 187, § 1, 52 Stat. 329, providing that purchase of supplies and equipment or procurement of services for Bureau of Mines might be made in open market without compliance with section 5 of former Title 41, Public Contracts, where amount involved did not exceed $100, was a provision of Interior Department appropriation act and was discontinued in acts subsequent to 1938 appropriation act.