478 Professor Thorpe [Feb. 15, 



account was afterwards sent by Dr. Bucli to Gilbert's ' Annalen/ with 

 Wohler's name at the bead of it. In his twentieth year he entered 

 the University of Marburg as a student of medicine, but all his 

 leisure time was devoted to chemical investigation. He discovered, 

 without knowing that Davy had anticipated him, the intensely poison- 

 ous iodide of cyanogen ; and in a little paper on cyanogen compounds, 

 communicated for him by Dr. Buch to Gilbert's ' Annalen,' we have 

 the first description of the remarkable behaviour of mercuric 

 thiocyanate on heating, which has led to its use in the so-called 

 " Pharaoh's serpents." 



Wohler, attracted by the fame of Leopold Gmelin, left Marburg 

 for Heidelberg, and in the old cloisters which at that time constituted 

 the University laboratory, he began the work on cyanic acid which 

 some four or five years later culminated in his great discovery 

 of the synthesis of urea. In 1823 he obtained his degree, and on 

 Gmelin's advice abandoned medicine for chemistry. The masterly 

 analytical skill of the great Swedish chemist Berzelius no less than 

 his labours towards the development of chemical theory had, at this 

 time, made him supreme among the chemists of Europe, and to Stock- 

 holm, therefore, Wohler determined to go. He was warmly wel- 

 comed by the illustrious Scandinavian chemist, of whom he has left us 

 an interesting sketch in his " Jugend-Erinnerungen eines Chemikcrs " 

 (Ber. Deuts. Chem. Gesell., 1875). Whilst at Stockholm he dis- 

 covered, among other products, some new compounds of tungsten, 

 notably the monoxychloride and the tungsten sodium-bronze 

 (Na2W309) which twenty-five years later was introduced into^the 

 arts as a bronze powder. 



After a couj)le of months spent in travel wdth Berzelius in 

 company with the two Brongniarts, Wohler, at the expiration of 

 his year's stay in Sweden, returned to Germany and jirepared to 

 settle at Heidelberg as " privat decent." On the recommendation 

 of Leopold von Buch, Poggcndorff and Mitscherlich, he was, how- 

 ever, appointed to the teachership of chemistry in the newly founded 

 Gewerbe Schule in Berlin. Wohler was now twenty-five, and in 

 possession of a laboratory which he could call his own. One of the 

 many problems which he at this time attacked was the isolation of 

 aluminium, which he succeeded in obtaining by the method which 

 nearly twenty years afterwards was worked out on a manufacturing 

 scale by Sainte-Claire Deville. Deville caused the first bar of the 

 metal thus procured to be struck as a medal, with the image of 

 Napoleon III. on the one side and the name of Wohler with the date 

 1827 on the other, and presented it to the German chemist. 



But of the twenty-two memoirs and papers which Poggendorfi"s 

 * Annalen ' exhibits as the outcome of Wohler's activity during his six 

 years' stay in Berlin, that on the artificial formation of urea is by far 

 the most important. Probably no single chemical discovery of this 

 century has exercised so great an influence on the develoj^ment of 



