Carbonic Acid Gas
"We have from time to time heard about the gas called carbonic acid," said Fred. "Teacher made some for us today. I"ll tell you how he did it, Norah.
"He put some small pieces of chalk into a bottle, which was fitted with a bent tube and a funnel. He poured enough water down the funnel to just cover the pieces of chalk, and then he added a little of a liquid which he called hydrochloric acid. Allat once a bubbling commenced round the pieces of chalk, and the bubbles rose up and burst on the surface of the liquid. They were bubbles of the new gas, carbonic acid. They came from the chalk.