The Enlightenment – the period of science following the Renaissance. Its driving feature was that reason was superior to superstition.
It is often felt that this is where Chemistry caught up with other great scientific advances elsewhere.
Joseph Black, was born in Bordeaux, France although his parents were British. He studied medicine and for his thesis investigated the affect of ‘white magnesia’ on ‘stones’ in the urinary system.
Part of his work involved heating his white magnesia with quicklime.
Quicklime was ultimately obtained by heating limestone.
After a series of careful measurements he realised that limestone lost mass when heated and so must have been making a gas. He collected this gas and found that it put out a candle flame. He realised that this gas was distributed in the air and stated to realise that air was not one gas but a mixture of gasses.
As you can probably deduce, this gas was ultimately found to be Carbon Dioxide.