Andre Marie Ampere who lived in the years 1775-1836, described the magnetic field occurring around the conductor in which the electric current flows.

Amadeo Avogadro Di Quaregna who lived in the years 1776-1856 studied molecules and their features. He formulated the law which said that in constant temperature and pressure the quantity of gas's molecules taking up the same space is the same. He stated also that the gram - molecule of every substance contained the same number of molecules (that quantity, evaluated in the year 1906, was called Avogadro's number).

Michael Faraday was the great chemist and physicist, who lived in the years 1791-1867. He set to research on electrochemistry - he formulated the laws of electrolysis which let the processes of electrolysis be better understood . He systematised electrochemical terms. He studied electromagnetic connections (he invented transformer and dynamo). He considered the interaction of atoms. He was of the opinion that the interaction is transported by the field; that means the ability of space to be distempered caused by some source. In his works he tried to explain the connection between atom and electric forces.

Rudolf Emanuel Clausius, who lived in years 1822-1888, was the German (born in Koszalin in Poland) physicist-atomist. Describing atom's motion he used mathematical laws of statistics. He discovered that the temperature of the body depended on chaotic movement of that body's atoms. He formed the second law of thermodynamics. According to it, the heat of the colder body can't flow spontaneous to the warmer body. Studying the chaotic movement of atoms he defined the mean free path i.e. the statistic distance which the molecule could cover between collisions.

James Clerk Maxwell, who lived in the years 1831-1879, formulated the law of the decomposition of gas molecular velocity (assuming that gas was composed of chaotically moving molecules). He studied internal friction in gases. Basing on atomistics, he explained the slowness of diffusion. The most important of Maxwell's works were the ones of electromagnetism. He gathered Faraday's theories and ideas and put them into mathematic form. Maxwell equalised the electric and the magnetic field. He foresaw electromagnetic waves subsistence and he evaluated the velocity of their propagation in the empty space - the speed of light.

Dymitrij Mendelejev, was the great Russian chemist, who lived in the year 1834-1907. Writing a handbook for students, setting elements in the order by their atomic mass he discovered a simply dependence - every eight elements had similar features. So he put the elements into eight columns. He didn't filled up all gapes because some of the elements were still unknown. In the year 1875 gal, the new element was discovered. Not long later skand and german were discovered too. For the subsistence and the features of them all Mendelejev predicted before. That was the proof that he was right making his table.

Johannes Diderik van der Walls, lived in the years 1837-1923. He was a Dutch scientist, who studied the forces subsisting between gas particles. He imagined that particles as balls between which there was an attractive force growing when molecules were approaching until putting them together. The regard that to that two forces let him put corrections into equation of gas law. He described in it the dependence between the pressure, volume and the temperature of the gas.

John William Strutt Rayleigh, the great scientist, who lived in the years 1842-1919, default with many problems of physics. Among the others, he tried to evaluate Avogadro's constant; he estimated quantities of the molecules of different compounds; he searched the occurrence of the surface tension, what let him evaluate the forces acted between the particles. In the year 1894 both with William Ramsay discovered the first of the helium-group gasses - argon.

Ludwig Eduard Boltzmann, who lived in the years 1844-1906 was the one of the most versatile physics of the 19th century. He searched occurrences in gases; he described a more general law of the decomposition of gas molecular velocity (the Maxwell-Boltzman law). In his researches on thermodynamics he introduced the conception of probability. He worked out the equation of gas transport - the law describing distempers transported in different kinds of gases - changes of temperature, velocity, density. That distempers are transported by collisions between molecules. The equation formulated by Boltzmann let diffusion, viscosity, heat conduction be better understood. It let also explain Hall effect (the formation of the electric field by the joint action of the outer magnetic field and the current flowing in the conductor).

Wilhelm Conrad Roentgen lived in the years 1845-1923. Among the other his researches he studied the occurrence of cathode radiation. That occurred while the electric current flowed through the tube filled with rare gas. The tube started to illuminate to the negative electrode. Invisible rays coming out of the cathode had to be responsible for that. He observed their interaction with metals. He noticed that fluorescent crystals, placed near the set of instruments used in the experiment, started to illuminate. That happened even when he conducted the experiment in absolutely darkness. That occurrence he tried to explain by the subsistence of unknown mysterious, new kind of radiation - X-radiation. Roentgen discovered that the radiation was absorbed by different materials in different degree. That let him make the first photo of alive person hand skeleton.

Henri Antoine Becquerel, who lived in the years 1852-1908, tried to find out whether during fluorescence besides visible light there was also the X-ray emission. To check whether it was so, he used photographic plates wrapped in lightproof paper. X-rays could permeate the paper and blacken the plates. On wrapped plates he put shoted samples of uranium. Plates were blacken. Becquerel said that was because they sent X-rays. But few days later he noticed that even non-shoted samples of uranium provocated the same effect. That was the first time when radiation was described.

William Ramsay lived in the years 1852-1916. In 1894 he and John Rayleigh both discovered a new element which Ramsay called argon. It didn't compound with any other elements and it didn't fit in periodic table. The table had to be enlarged by one column. A year later Ramsay discovered another element of that group - helium and in 1898 he isolated all noble gasses occurring in the air; that is: argon, neon, helium, krypton, xenon and in 1910 - radon. Apart from these researches he tried to interpretate Brownian movement explaining them as collisions of observed bodies and invisible particles of medium.

Hendrik Antoon Lorentz was a great scientist of the end of the 19th century. He lived in the years 1853-1928. He wanted to find the connection between the optical occurrences and electromagnetic occurrences. He created an electron theory describing electromagnetic occurrences in matter. In the theory he placed a formula defining the forces influencing the charge moving in the electric field. Today those forces we call Lorentz force.

Heinrich Rudolf Hertz, lived in the years 1857-1925. He searched electromagnetic waves - he proved that a fast vibrating charge, just like Maxwella foresaw it, is the source of electromagnetic waves. He also simplified formulas of Maxwella. Hertz discovered also that some metals emit minus particles under the influence of ultraviolet radiation. He noticed that electrical neutral metals become plus charged after the exposure.

Svante August Arrhenius who lived in the years 1859-1925, was a Swedish scientist. He created a modern theory of dissociation. He was the first to describe the acts of ions in the solution.

    The scientist of the 19th century explained many occurrences connected with electromagnetism and the kinetic theory of gases. X-raying was discovered. There appeared some new equipment based on electromagnetic occurrences. Soon they were used in practise in people's life and as the experimental equipment. At the and of the 19th century the first elementary molecule was finally discovered - the electron.