XXV 



At first Dumas lectured at this school on general, analytical, and 

 industrial chemistry. At a later period, when its financial position 

 permitted the appointment of additional chemical teachers, he con- 

 fined himself to either one or other of these branches. The lectures 

 on general chemistry he continued up to 1852, when he resigned in 

 favour of Cahonrs. 



The number and variety of lectures which Dumas had to deliver at 

 the Ecole Centrale immediately after its opening, in addition to his 

 duties at the Polytechnic School, rendered it an absolute necessity for 

 him to diminish his engagements elsewhere, so as to enable him to 

 find time for the various researches he had then in hand. Nor did he 

 hesitate (in 1829) to retire from the Professorship at the Royal 

 Athenaeum, to which Bussy was then appointed. The alleviation 

 thus obtained was not of long duration. In 1832 Guy-Lussac resigned 

 his chair at the Sorbonne, which, like a natural inheritance, fell to 

 Dumas ; and to this position, which he held up to 1868, when Henri 

 Ste. Claire-Deville, after having acted as his substitute since 1853, 

 became his successor, was soon added another important appointment. 

 Tor when (in 1835) Thenard withdrew from his Professorship at the 

 Ecole Polytechnique, the duties of the office devolved upon Dumas, 

 who for twelve years had been a Repetiteur at the School. Dumas 

 was, in fact, appointed, and remained in connexion with the Institu- 

 tion up to 1840, when he resigned in favour of Pelouze. The list of 

 his Professorial appointments, however, is not yet exhausted. After 

 the death of Deyeux (in 1839) he was induced, chiefly by Orfila, to 

 undertake the duties of the Chair of Chemistry in the Ecole de 

 Medecine. 



In these several positions Dumas had to lecture on very different 

 subjects : he had, moreover, to shape his courses according to the 

 traditions of the places in which he lectured, and to adjust them to the 

 different ages, acquirements, and wants of the students he addressed. 

 His unprecedented success as a lecturer is unequivocally proved by 

 the lively and lasting recollections which his lectures, addressed to 

 such a diversity of audiences, have left in the minds of his hearers. 

 Even those who have had the good fortune of attending but a single 

 one of his lectures will ever remember the clearness and precision 

 of his reasoning and the attractive grace of his delivery. 



But it was by no means only in lectures that Dumas has sown 

 broadcast the seeds of chemical science. He was, in fact, the first in 

 France to adopt that efficient system of laboratory teaching so happily 

 inaugurated by Liebig, which has ever since been a prominent feature 

 of the German Universities. The laboratory which he had established 

 in the Ecole Polytechnique, though well adapted for an experimental 

 inquirer working along with his assistant, was altogether unfit for the 

 reception of a number of pupils. That he might be able to associate 



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