XXXV11 



In the year 1862 appeared his great work, in two volumes, ' Der 

 chemische Process der Ernahrimg der Vegetabilien und die Naturgesetze 

 des Eeldbaues.' This was the crowning work of Liebig's agricultural 

 labours, and his doctrine is now universally recognized ; and no thought- 

 ful agriculturist ever now supposes that he need but add superphos- 

 phate or nitrogen or guano and his fields will be for ever fertile. It is 

 now in agriculture but a question of the best appliances necessary to do 

 justice to the theory of Liebig. In Germany agriculturists have thank- 

 fully acknowledged this by the foundation of the Liebig Stiftung. 



In close connexion with the subject of nutrition is Liebig's work on 

 flesh, which first gave us a more exact idea of the chemical composition 

 of muscle, that is by far the greatest and most massive part of our 

 bodily orgaus. One result of this work is the Liebig's Meat Extract, 

 now well known to the whole world, of which so much has been said, 

 and whose value has been as often over- as underrated. 



Liebig spent the remainder of his life at Munich, where he died on 

 the 10th of April, 1873. 



Augtjste Arthur de la Rive, born at Geneva on the 9th of October, 

 1801, was the son of Charles Gaspard de la Rive, Professor of Chemistry 

 and Physics in the Academy of Geneva. He studied first at the College 

 and then at the Academy. After working at science for a time he 

 devoted himself to the study of law for two or three years. He had 

 inherited his father's taste for science. In the year 1822 he became 

 deeply interested, in Ampere's investigations ; and when Ampere's theory 

 of the magnet had lost its best support, the young Auguste de la Rive 

 came to his assistance. He performed a series of delicate experiments, 

 which Ampere came expressly to Presinge, the country place of the 

 De la Rives, to witness. The memoir " On the Influence of Terrestrial 

 Magnetism upon a movable frame traversed by a Voltaic Current," 

 written by the young physicist on this occasion, contains not only the 

 new results which he had obtained, but the learned and conclusive theory 

 by which Ampere connects them with his own views, thenceforth com- 

 pletely triumphant. This first research not only brought him into con- 

 nexion with Ampere, but paved the way for his long and intimate 

 friendship with Faraday. 



In October 1823 he gave up his legal studies and succeeded M. Prevost 

 as Professor of Physique Generale at the Academy. On the occasion of 

 his candidateship he published a thesis, " Dissertation sur la partie de 

 l'optique qui traite des courbes dites caustiques." He had also to give 

 some lessons at the Academy and a public conference on the theory of 

 the pendulum. On the death of M. A. Pictet in 1825 he resigned the 

 chair of Physique Generale to succeed to that of Experimental Physics. 

 He often gave, in addition to his regular lessons, some special course on 

 Electro-chemistry, or courses for a general audience, conjointly with 

 M. Marcet, besides others for the industrial classes. 



