11 



the Giessen laboratory. This position he resigned after the first 

 year, leaving Will the sole control of the laboratory. Kopp remained 

 at Giessen nearly a quarter of a century, and all his most im- 

 portant experimental work was done there. In 1863 he received a 

 call from Heidelberg, which he accepted, and here he stayed until 

 his death, occupying himself with lectures on the history of che- 

 mistry and on chemical crystallography. He was repeatedly solicited 

 to accept a position in one of the larger Universities, notably in 

 Leipsig and in Berlin, but all attempts to draw him from his dear 

 Ruperto- Carolina were fruitless. " Even Bunsen alone," he was 

 wont to say, " keeps me fast in Heidelberg." 



Kopp's ' History of Chemistry ' is his greatest literary effort. 

 The first volume of it appeared in 1843, and the fourth and final 

 volume in 1847. By the publication of this classical work, Kopp, 

 when barely thirty years of age, suddenly found himself famous. 

 His life- long friend, von Hofmann, who was then at Giessen, has left 

 us the following account of the sensation which the work made on its 

 appearance : 



" With one accord his contemporaries recognised that here was a 

 production which, whether they regarded the thoroughness of re- 

 search that it displayed, or the manner in which the material 

 resulting from that research was sifted and arranged, was without a 

 parallel in the literature of any other country. And even to-day, 

 after the lapse of nearly half a century, there is no historical work on 

 chemistry that can be even remotely compared with it. Numbers of 

 books relating to the same subject, some of considerable merit, have 

 since been published in Germany and France, but it is not difficult to 

 perceive that they are all grounded on Kopp's great work." 



For upwards of forty years Kopp had it in contemplation to bring 

 out a new edition, and much of the later historical work he published, 

 such as his * Beitrage zur Geschichte der Chemie,' which appeared 

 between 1869 and 1875, and the ' Entwicklung der Chemie in der 

 neueren Zeit,' printed under the auspices of the Historical Commis- 

 sion of the Bavarian Academy in 1873, together with the two 

 volumes on * Die Alchemie in alterer und neuerer Zeit,' grew out of the 

 materials he had gathered together. " But," again to quote Hofmann, 

 " the better is here the enemy of the good. Kopp postponed the ' ver- 

 mehrte und verbesserte Auflage ' year after year, in the hope of 

 being able to make a fuller study of certain special periods. Who- 

 ever is familiar with the mass of profoundly interesting matter he 

 had accumulated, or who has had the opportunity of seeing the 

 bulky note-books in which it was stored, must deeply lament that the 

 hand which could alone arrange these treasures is now stiffened in 

 death." 



The literature of chemistry is further indebted to Kopp for the 



