Heraclitus in ancient Greece once regarded the whole world as "an eternal living fire". At that time, fire was regarded as the source of everything for many reasons. One of the reasons is that plants and other combustible substances often emit a lot of fire when burning. More importantly, fire can promote the transformation of matter, as if fire can educate everything. Therefore, alchemists also hope to turn other metals into gold with torches, because they see that fire can make things ever-changing. In short, in the eyes of the ancients, fire is the most active, active, dynamic and changeable thing in all things, and the whole world is constantly changing in fire. However, due to the limitations of scientific and technological conditions at that time, it was impossible to further investigate the nature of fire.
1from the end of the 7th century to 1774, when the French chemist lavoisier put forward the theory of burning oxygen, there was a "phlogiston theory" circulating in Europe, which was dominant.
Before the phlogiston theory was put forward, many people had carefully observed the burning phenomenon and made various comments. For example, Leonardo da Vinci, an Italian in the15th century, noticed that when burning, if there is no fresh air to supplement it, the burning cannot be carried out, that is to say, the burning phenomenon is inevitably related to the existence of air. In 1630, French doctor Rey further noticed that the weight of tin and lead increased after calcination. He thinks this is because air condenses on tin embers, just like dry sand absorbs water and becomes heavier. Later, in 1664, robert hooke (1635- 1703), a British physicist and chemist and discoverer of the law of solid elasticity, thought that flame was a mixed gas that caused chemical action. He pointed out that flame could not burn without air. But he still believes that the "sulfur" mentioned by the alchemist is released from the combustion body during the combustion process.
By the second half of the seventeenth century, the metaphysical and mechanical materialistic view of nature had basically taken shape. The indispensable material particles and mechanical forces have become the basis of all natural phenomena. In order to clarify the nature of matter, people often "cite some kind of force-gravity, buoyancy, electric contact force, etc." -on all unexplained phenomena, I think this can explain all these phenomena. If none of these are applicable, then give some things that people don't know: light elements, heat elements, electric elements, etc.
What is fire? Boyle, a famous British chemist, resolutely opposes the wrong view that fire is the embodiment of heat and dryness; It also opposes that alchemists and scholasticism regard fire as a mysterious concept decomposed from objects. In his view, fire should be a real material element composed of heavy "fire particles". From this point of view, he thinks that when plants and fuels burn, most of them become phlogiston and are dispersed into the air, leaving only insignificant ashes compared with the weight of the original object itself. 1603, he calcined copper, iron, lead and tin in a closed container, and carefully and quantitatively studied their weight gain after calcination. Finally, he thinks that when the metal is calcined, the fire particles emitted by the fuel will penetrate the container wall, enter the metal and combine with them to form calcined ash heavier than the metal itself. Therefore, his explanation of calcined heavy metal can be expressed as: metal particles = calcined ash.
On this basis, if he can go further, it is possible to make a major breakthrough in the understanding of fire and burning phenomena. But Boyle only noticed the increase of metal weight in the closed container in the experiment; And neglected to investigate whether the air in close contact with the metal has also changed. As a result, in order to illustrate the experimental facts, we had to find a "fire particle" to fill in the numbers. The one-sidedness of his experimental observation prevented him from correctly revealing the secrets of fire and burning phenomena.