 We all benefit from the achievements of chemistry on a daily basis but few of us will know about the history of chemistry. The world's first submarine was designed and built by the mysterious and secretive Dutch inventor and alchemist Cornelis Drebbel. The submarine sailed under the water and river Thames in 1620 with 12 rowers and the air in the submarine was refreshed by a mysterious substance. The diagram which I'm showing you was published in a book which was written by Drebbel. It was called Treatise on Nature and it was published in 1608. Could this diagram by any chance be showing the thermal decomposition of potassium nitrate to make oxygen? The answer to this question is one of the many talks, many aspects of my talk which I will be giving which I will be discussing the one of the greatest discoveries of science the fact that air is a mixture of gases. I will now briefly show you an experiment. This is one of many experiments which I will be showing and explaining during my talk on the historical highlights of chemistry.