Joseph Priestley’s Joseph Priestley on oxygen was inspired by Blake’s discovery of CO 2 in calcined limestone, using convex lenses to concentrate sunlight to burn or break down some substances into gases. On 1774, the Joseph Priestley finally succeeded in producing oxygen, an event of great significance in the history of chemistry.

   His experiment was very simple. He put the mercuric oxide in a glass bottle filled with mercury. Then he placed the glass bottle upside down in a mercury tank. The glass bottle was completely filled with mercury. He then focused the Sun’s light with a Convex Lens, which shone on the mercury oxide, heating it. 

After long-term heating, the temperature gradually increased, the oxidation of mercury decomposition into mercury, and the release of oxygen. As a result, oxygen builds up to drain the mercury from the bottle, lowering the mercury level. The gas space volume increases until it is three or four times the volume of mercuric oxide. 

But he did not know that the pure gas he produced was oxygen. Nevertheless, the careful Joseph Priestley did many experiments to understand the nature of the gas and how it differed from other kinds of “Air”. His methodology:

1. He put the gas in a glass bottle and poured some water into it. The gas did not dissolve.

 2. He put the burning candle into the gas, and the candle gave off a bright light. 

3. He put a mouse into a bottle filled with the gas. The mouse was alive and well, and he guessed that people might feel better if they inhaled it. 

4. He used a glass tube to draw the oxygen from the big bottle into his lungs, i felt very happy. My lungs felt as if I were breathing air. There was nothing wrong with it.

   Moreover, after inhaling this kind of gas, for a long time, the body is still very relaxed and happy. Perhaps, one day, who is to say that this gas will not become a fashionable luxury? But, uh... Now, there are only two mice and myself in the world who can enjoy the pleasure of this gas, the gas has the role of combustion, assisted respiration, these properties and general air similar, but a stronger role. However, he misinterpreted the new gas as Phlogiston and called the resulting oxygen “Dephlogiston air”. The name is not appropriate due to the application of the wrong theory.