502 



NA TURE 



[February 2^, 1910 



and placed in the vicinity of that of Oersted in the court- 

 yard of the Polytechnic High School of Copeniiagen. 

 Thomsen, in fact, played many parts in the intellectual, 

 industrial, and social development of Denmark. To Europe 

 in general he was mainly known as a distinguished man of 

 science. By his fellow-citizens he was further recognised 

 as an educationist of high ideals, actuated by a strong 

 common sense and a stern devotion to duty ; as an able 

 and sagacious administrator ; as a successful technologist 

 and the creator of an important and lucrative industry based 

 upon his own discoveries ; and as a man of forceful 

 character, who brought his authority, skill, and knowledge 

 i.f men and affairs to the service of the communal life of 

 Copenhagen. 



Thomsen was a municipal councillor of that city for 

 more than a third of a century. He occupied a commanding 

 position on the Council, and was invariably listened to with 

 respect. The gas, water, and sewage works of Copenhagen 

 are among the monuments to his civic activity. From 

 1882 up to the time of his death he was a member of the 

 Harbour Board of the port. In these respects Thomsen 

 sought to realise Priestley's ideal of the perfect man— that 

 he .should be a good citizen first and a man of science 

 afterwards. 



Hans Peter Jurgen Julius Thomsen was born in Copen- 

 hagen on February 16, 1826. He was educated at the 

 church school of St. Peter in that city, and subsequently 

 at von Westens Institute. In 1843 he commenced his 

 studies at the Polytechnic, and in 1846 graduated there in 

 applied science, and became an assistant to Prof. E. A. 

 Scharling. Of his earliest years comparatively little is known. 

 Thomsen, always a reserved and taciturn man, talked little 

 about himself even to his intimate friends — and least of all 

 about the days of his youth. It was known to a few that 

 these days had not been smooth. Those who were best 

 informed were conscious that to these early struggles much 

 of that dour and resolute nature which formed a dis- 

 tinguishing trait in his character was due. Thomsen, 

 indeed, began life as a fighter, and a fighter he remained to 

 the end of his four-score years. 



_ In 1847, he became assistant to Forchhammer, passing 

 rich, like Goldsmith's pedagogue, on ifll. a year. Georg 

 Forchhammer, whose earliest work dates back to the period 

 when Berzelius was in his prime, was an active and 

 industrious investigator of the old school, mainly in in- 

 organic chemistry, and more particularly on problems of 

 chemical geology and physiography. He was a frequent 

 visitor to this country, and was well known to early 

 members of the British Association. Although doubtless 

 influenced, in common with all teachers in northern Europe, 

 by the e.xample and methods of Berzelius, such influence 

 as he himself was able to exert died with him. Forch- 

 hammer attracted few pupils, and created no school, and 

 Thomsen probably derived no inspiration or acquired any 

 stimulus from this association. For a time Thomsen 

 supplemented his scanty income by teaching agricultural 

 chemistry at the Polytechnic. In 1853 he obtained a 

 travelling scholarship, and spent a year in visiting German 

 and French laboratories. He probably owed this scholar- 

 ship in great measure to his first contribution to the 

 literature of chemistry, namely, his memoir, " Bidrag til en 

 Thermochemisk System " (contributions to a thermo- 

 chemical system), communicated to the Royal Society of 

 Sciences of Copenhagen in 1852, and for which he received 

 the silver medal of the society and a sum of ten guineas 

 to enable him to procure a more accurate apparatus. In 

 this memoir he sought to develop the chemical side of the 

 mechanical theory of heat, doubtless under the influence of 

 Ludwig Augustus Colding, an engineer in the service of 

 the Municipality of Copenhagen, and a pioneer, like Mayer, 

 in the development of that theory. Indeed, the Danes now 

 claim for Colding, who had made experiments on the relation 

 between work and heat as far back as 1842, but whose 

 laboijrs were practically ignored by his contemporaries, the 

 position which the Germans assign to Mayer (see Mach's 

 " Development of the Theory of Heat "). In 1861 Thomsen 

 further developed his ideas in a memoir on the " General 

 Nature of Chemical Processes, and on a Theory of Affinity 

 Based Thereon," published in the Transactions of the 

 Danish Academy of Sciences. In this paper he laid ihe 

 foundations of the chief scientific work of his life. 

 NO. 2104, VOL. 82] 



In 1.S53 Thomsen patented a method of obtaining soda 

 from cryolite, so-called "Greenland," or ice-spar, a 

 naturally occurring fluoride of sodium and aluminium, 

 .MjFj.eNaF, found largely, indeed, almost exclusively, in 

 Greenland, and particularly at Ivigtut. It derives its 

 mineralogical name from its ice-like appearance and ready 

 fusibility even in the flame of a candle. It seems to have 

 been first brought to Europe in 1794, and to have been 

 described by -Schumacher in the following year. Klaproth 

 first showed that it contained soda, and its composition was 

 further established by Vauquelin, Berzelius, and Deville. 



Thomsen 's process consists in heating 'a finely divided 

 mixture of cryolite and chalk in a reverberatory furnace, 

 whereby carbon dioxide is expelled and calcium fluoride and 

 sodium alumlnate are formed. The roasted mass is 

 lixiviated with water, so as to dissolve out the sodium 

 aluminate, which is then treated with carbon dioxide. 

 ."Mumina is precipitated, and sodium carbonate remains in 

 solution. The alumina is either sold as such or converted 

 into sulphate (co-called " concentrated alum " or " alum- 

 cake "), and the sodium carbonate is separated by crystal- 

 lisation. Both products are obtained in a remarkably pure 

 condition, and the cryolite-soda yields excellent " caustic." 



Thomsen 's process, although simple enough in principle, 

 requires considerable skill and pains in its practical execu- 

 tion, and most of the manufacturing details were worked 

 out by him, or under his direction. Success largely depends 

 upon the maintenance of a proper temperature ; the decom- 

 position begins below a red-heat, but requires to be finished 

 at that temperature, and care must be taken to avoid 

 fusion or even sintering of the mass. In 1854 Thomsen 

 obtained the exclusive right of mining for cryolite and of 

 working up the mineral in Denmark for soda and alumina. 

 Actual manufacturing operations were begun on a small 

 scale in 1S57, and in the following year Thomsen planned 

 the present large factory at Oeresund, near Copenhagen, 

 which was opened on his thirty-fourth birthday. The 

 importance of this industry to Denmark may be seen from 

 the circumstance that during the fifty years of its existence 

 the firm have paid the Danish Government nearly 300,oooi. 

 for the concession. Other factories were started in Ger- 

 many, Bohemia, and Poland, but met with little success. The 

 Pennsylvania Salt-manufacturing Company at Natrona, near 

 Pittsburg, eventually obtained the right to work up two- 

 thirds of all the cryolite mined in Greenland. From the 

 start Thomsen took a large share in the management of 

 the Oeresund works, and by his energy, foresight, and skill 

 placed the undertaking on a sound commercial basis. 



Although Thomsen died a rich man, mainly as the result 

 of the industry he created, in the outset of his career as a 

 teacher and a technologist his means were very straitened. 

 He came of poor parents, of no social position or influence, 

 and they were unable to further his inclinations towards an 

 academical career. In 1854 he applied unsucce-^sfully for a 

 position as teacher of chemistry at the Military High School 

 in Copenhagen. During three years — from 1856 to 1859 — 

 while still engaged in developing his cryolite process, he 

 acted as an adjuster of weights and measures to the 

 Municipality of Copenhagen. It was a poorlv paid position, 

 but it kept the wolf from the door. \t about this period 

 he betook himself to literature, and published a popular book 

 on general subjects connected with physics and chemistry — 

 somewhat in the style of Helmholtz's well-known work — 

 entitled "Travels in Scientific Regions," which had a 

 considerable measure of success. He was, however, not 

 altogether unknown even at this time as an author, since in 

 1853 he had collaborated with his friend Colding in pro- 

 ducing a memoir on the causes of the spread of cholera and 

 on the methods of prevention, which attracted much 

 attention at the time of its appearance. 



In 1859, whilst engaged in the Oeresund factory, he 

 again applied to the authorities for a position as teacher at 

 the Military High School, and succeeded in obtaining an 

 appointment to a lectureship in physics, which he held 

 until 1866. During his tenure of this office he devised his 

 polarisation battery, which received many awards at inter- 

 national exhibitions and was used for a time in the Danish 

 telegraph service. 



In 1859-60 he was " vicarius " for Scharling at the 

 University, and in 1865 became a teacher, and in the 

 following year professor of chemistry and director of the 



