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HISTORY OF SCIENCE AND TECHNOLOGY
Axel Frederik Cronstedt 1722 - 1765
Axel Cronstedt was born in Ströpsta, Sweden - a town about 40 kilometres south west of Stockholm. His father, Gabriel Olderman Cronstedt was a military man, rising through the ranks to General and Head of the Engineering Corps. Axel Cronstedt learnt a lot about engineering from his father and, in 1738, he entered the University of Uppsala to read mathematics. During his university studies Cronstedt was taught by Johan Gottschalk Wallerius, who held the first professorship in chemistry at Uppsala, and Anders Celcius, an astronomer best known for his work on temperature scales.
Axel Frederik Cronstedt (from a medal c. 1870)
Cronstedt was unable to complete his university course. Between 1741 and 1743 Sweden was at war with Russia and Cronstedt was called up to join the forces. He served in the engineering corps as his father's secretary and they travelled the country inspecting military fortifications. These inspections included visits to silver, lead and copper mines. Cronstedt developed a keen interest in mineralogy and metallurgy, quickly developing expertise in these fields; so much so that he presented papers to the Swedish Board of Mines and the Swedish Academy of Science.
In 1746 Cronstedt took a course in experimental chemistry at the Royal Mining Laboratory in Stockholm. It was here that he met Georg Brandt (who identified cobalt) and Sven Rinman. Rinman is often referred to as the 'father of mineralogy in Sweden' and he was a member of the Royal Mining Mineralogy Board. He and Cronstedt formed a life-time friendship.
Through his connection with Brandt, Cronstedt was able to visit Brandt's copper mines in Riddarhyattan and his friendship with Rinnan secured him a position in the chemistry laboratory at the Royal Mining Association in Stockholm. By 1748 Cronstedt had been appointed as assistant superintendent of mines and was assigned as the Director of East and West Bergslagen in central Sweden. This position involved supervision of the Skiss silver foundries in South Dalarna and gave Cronstedt access to state of the art laboratory facilities.
Cronstedt developed a portable apparatus that proved very effective in the analysis of small mineral samples. He adapted the blowpipe used by goldsmiths to solder by making a brass tube that could blow air through a candle flame to direct the heat. Depending on where the blowpipe was positioned in the candle flame would provide either a "phlogiston rich" jet (so able to oxidize a section of the mineral source) or a "phlogiston poor" jet (so able to reduce it).
The blowpipe method proved to be very accurate for its time. Cronstedt recorded any colour changes, both in the mineral sample and the jet, as well as any other visible effects, such as decomposition, sublimation and fusion. Because the blowpipe apparatus was easy to carry around for use in the field or even at home, it became popular with the scientists of the day. The blowpipe kit was in no small way responsible for the future identification of at least eleven elements.
Cronstedt discovered nickel in 1748 (see details to the left), calling it 'vide infa'. He presented the results of his analysis to the Swedish Academy of Science in 1751 and 1754, by this time naming nickel as a new semi-metal. In the 1750s the phlogiston theory reigned and a metal was considered to be the metal calx (oxide) plus phlogiston. Twenty years earlier Georg Brandt had published analytical tests to distinguish between the six known semi-metals - arsenic, zinc, bismuth, antimony, mercury and cobalt. The only accepted metals were those known since antiquity - gold, silver, lead, iron, copper and tin. The mineralogists of the day were skeptical about Cronstedt new, seventh semi-metal, suggesting it was likely to be a mixture of metals and/or semi-metals already identified.
Little wonder then that Cronstedt published his book "Fönsök Mineralogiens eller mineral-Rickets upställing" (Arrangement of the Mineral Kingdom) under an assumed name. He was particularly concerned about the reaction of two revered scientists. The first was Andreas Linneas who had, rather rashly, attempted to classify minerals using the same reasoning that he had used to classify the animal kingdom. The other was Cronstedt's old university professor, Wallerius, who had published a book entitled "Minerology" that was made redundant by Cronstedt's publication. In fact, Cronstedt need not have worried - his publication was very well received and mineralogists in other countries eagerly awaited their translations!
In 1760 Cronstedt married Gertrund Charlotta Soderhielm and a year later they moved to Nisshytte, about 50 kilometres north of Riddarhyttan. Cronstedt bought a local iron foundry but, more and more, he retreated to looking after his garden. He did make occasional visits to Stockholm to attend meetings and it was on his return from one of these meetings in 1765 that he fell ill. His health rapidly deteriorated and he died not long after, aged only forty two.
Ten years after Cronstedt's death, Toben Bergman isolated a pure sample of nickel. By the end of the 18th century Antoine Lavoisier had published his "Treatise" and included nickel as one of the eleven semi-metals then identified.
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