Glass. Chemical and optical glassware and scientific apparatus, hearings on H. R. 3734. to provide revenue for Government and to establish manufacture of optical glassware in United States, H. R. 3735, to provide revenue for Government and to establish manufacture of chemical glassware in United States, and H. R. 4386. to provide revenue for Government and to establish manufacture of philosophical, scientific, and laboratory apparatus in United States, June 11-13, 1919.