from 1848 to 1851—of political service, in which he represented the department of the Lower Rhine in the Constituent Assembly, and was nominated Councilor of State. He discharged the duties of these offices—which he had accepted from motives of patriotism alone—while, his political activity being regarded as merely temporary and for an emergency, his professorship at the Conservatory was kept open for him. Having bade a final good-by to politics in December, 1851, he used afterward to say, "There are few men of science who have succeeded in it, and science has always lost by it." But he always followed political events with a lively interest. Although his liberal and republican opinions were subjected to more than one blow from the events which were enacted in France, he did not consider it his duty to refuse the distinctions which were addressed to the man of science; and, while he held himself apart from the official world, he had occasion to give Napoleon III some good advice—which was not followed—concerning the expedition to Mexico. By his marriage, in 1833, with Mile. Le Bel, an Alsacian heiress, M. Boussingault became joint proprietor, with his brother-in-law, of the fine estate of Bechelbronn, in the Lower Rhine. The cultivation of this farm afforded excellent opportunities for experiments on the applications of chemistry to agriculture, concerning which it also suggested many questions; and the skill which had been cultivated and so creditably employed among the volcanoes and in the pampas of South America, now found a more practical field for its exercise in the investigation of matters which touched the vital interests of the nation, and, individually, of a large proportion of its members. These investigations laid the foundation of the science of agricultural chemistry as it is studied and practiced to-day; and Boussingault's French friends claim, not without reason, that his Bechelbronn farm was the prototype of the farm at Rothamsted, in England, and furnished the model after which the German laboratories for agricultural investigation were planned.
M. Boussingault's greatest scientific work, that for which he was most famous, was connected with his experiments upon the value of food-rations and the influence of various chemical agents upon the growth of plants; and those to ascertain whence plants derive their constituent elements. When he began them very little was definitely known on these subjects; even the composition of hay was not correctly understood. It was not his privilege to carry these inquiries to a complete result; but he made the initiatory intelligent efforts toward solving them, set the work well afoot, and pointed out to those who are still seeking with accumulated skill and intelligence the way which they should pursue. "The processes," says M. Dehérain, "for the estimation of carbon, hydrogen, and nitrogen had been made effective; the methods
