Carbon Dioxide Gas: Chalk and Dilute Acid, Collected from the Bottom Up

Carbon dioxide, Black's fixed air, is locked up in chalk and limestone, and an acid sets it free. It is half as heavy again as air, so it can be poured from one vessel into another and fills a bottle from the bottom up. In a closed space it suffocates: work in an open, airy room. The picture: our diagram of the generating bottle, the delivery tube and the candle test.