Description

Clear 500 mL Pyrex straight-sided bottle with a ground-glass opening and a stopper at the top. The front of the bottle has a ground-glass rectangle labeled ammonium hydroxide NH4OH.

This bottle is made of Pyrex, the Corning trade name for borosilicate glass. The Corning Glass Works developed a lead-free borosilicate glass as a consumer product in 1915. Though it was first used in consumer products like pie plates and casserole dishes, WWI-era shortages in laboratory equipment (which were mainly manufactured in Germany) led the company to expand into making glass labware.