Among the scientists who studied the properties of radium was Ernest Rutherford, one of England's greatest physicists, honorary member of the U.S.S.R. Academy of Sciences and a number of other Academies.

He discovered that radium gave off three different types of rays and denoted them by the first letters of the Greek alphabet. (Following his example, we still call them alpha, beta and gamma rays). The first of them, i.e., the alpha rays, also called alpha particles, turned out to be changed electrically with a positive charge. The beta rays were found to consist of negative electrons, while the gamma rays proved to be just waves like X-rays but of much shorter wave-length.

Rutherford performed a series of experiments first with the rays of radium and later with uranium. As a result, he established the nuclear theory of atomic structure and proved that the atom consisted of electrons revolving around a very small but very heavy nucleus. He performed the first successful atom-smashing experiment in 1919.

The discovery of the neutron in 1932 was another important step leading to the understanding of nuclear structure. It made it clear that the nucleus is composed of protons and neutrons, the protons being tiny particles with a positive electric charge and the neutrons — particles without any charge.

Then the year 1934 brought a new scientific event which attracted general attention not to speak of its being of tremendous importance for world science. Irene Curie, daughter of Pierre and Marie Curie, the discoverers of radium, and her husband Frederic Joliot Curie discovered a new phenomenon-artificial radioactivity (also called "induced radioactivity"). They proved that radioactivity could be produced artificially in the laboratory in elements which were not naturally radioactive. By studying the artificial activity of uranium generated by neutrons, they furthered the discovery of nuclear fission which, in its turn, is the foundation of atomic physics.

In the course of the next five years, the most outstanding nuclear physicists both in Europe and America worked on the problem of nuclear fission. The turning point in the search for atomic energy came in 1939. In that year, it was discovered that under proper circumstances, the neutron was capable of breaking up the nucleus of a urani­um atom into two parts which fly apart with high relative velocity. Besides its releasing tremendous amounts of energy the phenomenon termed fission produced 2 or 3 fresh neutrons. Two things became apparent. First: if one of these 2 or 3 neutrons could be made to produce another fission, the process would be self-sustaining (i.e., result in chain reaction). Second: ordinary uranium neither underwent fission nor could serve as a source of atomic energy. It is Uranium 235, a particular isotope of uranium, which undergoes fission and is capable of releasing an enormous amount of power.

The first atomic-power station in the world with a capacity of 5,000 kw was put into operation in the Soviet Union in June 1954. Nuclear power generation has made tremendous progress since then and scores of similar power plants are now operating in the world. In this country the total capacity of such plants has reached a million kilowatts. In this connection one can't but mention the "Romashka". The world's first atomic power plant, the Romashka, with direct conversion of atomic energy into electric energy without any rotating machinery, i. e., without going through mechanical energy was developed in the USSR and has been in operation for some years.