Arrhenius was a brilliant student who learned to read at the age of three and graduated from secondary school as the youngest and brightest in his class. University studies in chemistry, physics and mathematics then followed in Uppsala where he also received his doctoral degree in 1884. His thesis on the galvanic conduction of electrolytes marked a breakthrough in chemistry because it explained the conductivity of the electrolytes by dissociation into positive and negative ions. This revolutionary theory was met with much opposition but became gradually accepted. The early proponents of the theory were W. Ostwald and J.H. vant Hoff who together with Arrhenius are considered as founders of modern physical chemistry. Arrhenius was rewarded in 1903 with the Nobel Prize in Chemistry.

In 1891 Arrhenius moved to the newly founded University of Stockholm where four years later his post was converted to a professorship in physics. In 1905 Arrhenius was appointed director of the Nobel Institute for Physical Chemistry in Stockholm. During his later years Arrhenius became increasingly interested in cosmic physics and the origin of life on earth. He suggested that life had begun when living spores had wandered through the empty space to earth. He was also one of the first scientists to study the influence of carbon dioxide on the earth’s temperature, which is now known as the “greenhouse effect”.

Berzelius lost both his parents in his childhood but nevertheless received good secondary education in Linköping and was able to enrol in 1796 at the University of Uppsala to study medicine. During medical studies he was taught chemistry by A.G. Ekeberg, the discoverer of tantalum.

His first publication in 1800 dealt with the analysis of Medevi spa water but his doctoral thesis two years later was of medical nature discussing the effects of galvanotherapy. Berzelius preferred chemistry to medicine but had to first serve as regional physician near Stockholm before the wealthy mine-owner W. Hisinger provided him with laboratory facilities in Stockholm. The collaboration with Hisinger lead to the discovery of a new element, cerium, in 1803 and helped him to obtain a professorship of chemistry at the Royal Carolinian Medico-Surgical Institute. He gave up this post after being elected secretary of the Royal Academy of Sciences.

The research of Berzelius was characterised by systematic diligence, chemical instinct and experimental precision unparalleled by other 19th century researchers. Besides cerium, several other elements (selenium, silicon, thorium) were discovered by him and the present chemical symbols were suggested by him. His determination of accurate atomic weights based on thousands of analyses allowed the composition of chemical compounds to be ascertained and corroborated the law of definite proportions. The early experiments with electricity and electrolysis lead Berzelius to develop the dualistic theory of bonding which could be successfully applied to inorganic compounds but not to organic ones.

Berzelius was also a prolific writer whose Textbook of Chemistry ran through several editions and was translated into five languages. Even more influential was the series of Annual Reports written by Berzelius from 1821 until his death. In these reports, which year by year grew in size, Berzelius summarised the most important achievements of the previous year and gave his judgement. Often he gave an explanation and coined a name for a new phenomenon such as catalysis and polymerisation. Berzelius was undoubtedly the leading chemical authority in Europe during the first half of the 19th century. His influence was further strengthened by extensive correspondence and through students which included among others F. Wöhler, E. Mitscherlich and the Rose brothers.