Examples from literature

• Air once breathed has lost the chief part of its oxygen, and acquired a proportionate increase of carbonic acid gas. 
• If it precipitates on adding lime water, it is carbonic acid. 
• The bicarbonate is decomposed, pure carbonic acid being given off. 
• This sweet cider ferments, and the sugar part of it changes into carbonic acid gas and alcohol. 
• Thus air which has been breathed has lost about five per cent. of oxygen and has gained nearly five per cent. of carbonic acid.