They condensed oxygen

Zygmunt Wróblewski and Karol Olszewski were the first in the world to liquefy several so-called permanent gases. The above scientists were professors at the Jagiellonian University at the end of the XNUMXth century. There are three physical states in nature: solid, liquid and gaseous. When heated, solids turn into a liquid (for example, ice into water, iron can also be melted), but a liquid? into gases (e.g. gasoline leaks, water evaporation). Scientists wondered: is the reverse process possible? Is it possible, for example, to make gas liquefied or even solid?

scientists immortalized on a postage stamp

Of course, it was quickly discovered that if a liquid body turns into a gas when heated, then the gas can turn into a liquid state. when cooling to him. Therefore, attempts were made to liquefy gases by cooling, and it turned out that sulfur dioxide, carbon dioxide, chlorine and other gases can be condensed with a relatively small decrease in temperature. It was then discovered that gases could be liquefied using high blood pressure. By using both measures together, almost all gases can be liquefied. However, liquefy nitric oxide, methane, oxygen, nitrogen, carbon monoxide and air. They were named persistent gases.

However, in order to break the resistance of permanent gases, ever lower temperatures and higher pressures were used. It was assumed that any gas above a certain temperature could not condense, even despite the highest pressure. Of course, this temperature was different for each gas.

Reaching very low temperatures was not handled very well. For example, Michal Faraday mixed solidified carbon dioxide with ether and then lowered the pressure in this vessel. The carbon dioxide and ether were then evaporated; during evaporation, they took heat from the environment and thus cooled the environment to a temperature of -110 ° C (of course, in isothermal vessels).

It was observed that if any gas was applied, decrease in temperature and increase in pressure, and then at the last moment the pressure was sharply loweredthe temperature dropped just as fast. In addition, the so-called cascade method. In general terms, it is based on the fact that several gases are chosen, each of which condenses with increasing difficulty and at increasingly lower temperatures. Under the influence of, for example, ice and salt, the first gas condenses; By reducing the pressure in a vessel with a gas, a significant decrease in its temperature is achieved. In the vessel with the first gas there is a cylinder with the second gas, also under pressure. The latter, cooled by the first gas and again depressurized, condenses and gives a temperature much lower than that of the first gas. The cylinder with the second gas contains the third, and so on. Probably, this is how the temperature of -240 ° C was obtained.

Olshevsky and Vrublevsky decided to use both methods, i.e., first the cascade method, in order to raise the pressure, and then sharply lower it. Compressing gases at high pressure can be dangerous and the equipment used is very sophisticated. For example, ethylene and oxygen form an explosive mixture with the force of dynamite. During one of the eruptions of Vrublevsky he just accidentally saved a lifebecause at that moment he was only a few steps away from the camera; The next day, Olshevsky was again seriously injured, because a metal cylinder containing ethylene and oxygen exploded right next to him.

Finally, on April 9, 1883, our scientists were able to announce that they liquefied oxygenthat it is completely liquid and colorless. Thus, the two Krakow professors were ahead of all European science.

Soon after, they liquefied nitrogen, carbon monoxide and air. So they proved that "resistant gases" do not exist, and developed a system for obtaining very low temperatures.