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.