DUMAS, JEAN B. A. 



DYNAMITE-GUN, THE. 273 



Tramnatieene. This preparation is much in 

 vogue in Vienna in the treatment of the com- 

 mon skin-disease, psoriasis (" tetter "). It con- 

 sists of one part of gutta-percha dissolved in 

 ten parts of chloroform. A semi-solid, sticky 

 mass is formed, which is applied to the af- 

 fected parts with a brush, and makes a thin, 

 tenacious coating, which adheres to the skin 

 for a few days and then scales off, leaving it 

 smooth and somewhat discolored. Kaposi 

 considers this the most effective means for 

 combating this obstinate malady. 



DUMAS, JEAN BAPTISTE ANDR&, a French 

 chemist, born in Alais, July 14, 1800 ; died April 

 11, 1884. He was apprenticed to an apothecary 

 in his native town, removed to Geneva, walk- 

 ing all the way, in 1816, and there continued 

 his studies under the direction of Caudolle, 

 Pictet, and La Rive. His investigations with 

 Prevost soon brought him into prominence. 

 His first paper, "On a New Process for the 

 Physiological Analysis of Blood," was pub- 

 lished in the " Bibliotheque Universelle de 

 Geneve." His work attracted the attention 

 of Humboldt, who visited him while passing 

 through Geneva. He removed to Paris in 

 1823, and soon became the Repetiteur de Chi- 

 inie under Thenard at the Ecole Polytechnique, 

 and subsequently succeeded Robiquet in the 

 chair of Chemistry at the Athenaeum. He be- 

 came intimate with that galaxy of brilliant in- 

 vestigators whose scientific researches are so 

 prominent in the early history of the natural 

 sciences. Among these was the younger Bron- 

 gniart and Victor Audouin, who, with Dumas, 

 in 1824 founded the "Annales des Sciences 

 Naturelles." In 1826 he married Mile. Her- 

 minie Brongniart, daughter of the illustrious 

 geologist and sister of his editorial colleague. 

 During the same year he published a paper 

 "On some Points of the Atomic Theory," 

 which produced a powerful impression at the 

 time, and has had lasting effects on the de- 

 velopment of chemical philosophy. His at- 

 tention was again directed to chemistry, and 

 his life-work thenceforth was almost exclu- 

 sively dedicated to this science. The estab- 

 lishment of the Ecole Central des Arts et 

 Manufactures, in 1829, was largely due to his 

 energy and perseverance. The department of 

 chemistry was under his supervision, and his 

 lectures continued till 1852. He presided over 

 the council of this celebrated school, with but 

 one short interruption, from its inception. 

 Gay-Lussac resigned the chair of Chemistry 

 at the Sorbonne in 1832; the place was of- 

 fered to Dumas, and his lectures continued 

 till 1868. In 1835 Thenard withdrew from 

 his chair at the Ecole Polytechnique, and his 

 duties fell upon Dumas, whose labors were 

 again increased in 1839, when he became the 

 occupant of the chair of Chemistry at the cole 

 de MSdecine. His lectures at this latter insti- 

 tution were the cause of his celebrated contro- 

 versy with Liebig in regard to the formation 

 of fat in the human system. This discussion 

 VOL. xxiv. 18 A 



was ultimately decided in favor of Liebig. It 

 is impossible to refer to the many memoirs 

 published by Dumas. These appeared in the 

 "Comptes Rendus" and other scientific peri- 

 odicals, including the "Annales de Chimie et 

 de Physique," of which journal he was editor 

 for upward of forty years. Two of his works 

 have become classical, the " Trait6 de Chimie 

 Applique"e aux Arts," and the "Lemons de 

 Philosophie Chimique." His parliamentary 

 career began shortly after the Revolution of 

 1848. Under the presidency of Louis Napo- 

 leon, he filled the office of Minister of Agri- 

 culture and Commerce. During the second 

 empire he was elevated to the rank of Sena- 

 tor. Such subjects as " Copper Coinage," 

 "Laws of Drainage," "Preservation of the 

 Mineral Springs of France," and "The Organi- 

 zation of Medicine," were those on which he 

 addressed the Senate, and from which his repu- 

 tation in political circles was made. Dumas 

 served on many, if not all, of the scientific 

 commissions called into existence by the Gov- 

 ernment. The reports on the claims of Le 

 Blanc, the discoverer of the process by which 

 sea-salt was converted into soda-ash, that of 

 the Phylloxera Commission, and more recent- 

 ly that of the International Commission on 

 Weights and Measures, were prepared by him. 

 In 1868 he became one of the perpetual secre- 

 taries of the Academy of Sciences. He suc- 

 ceeded Guizot in the French Academy. In 

 1843 the Royal Society awarded him the Cop- 

 ley medal, and in 1869 he was the recipient of 

 the Faraday medal given by the London Chemi- 

 cal Society. " Nature," in an extra number 

 for Feb. 6, 1880, contains, from. the pen of 

 Prof. A. W. Hofmann, of Berlin, a most excel- 

 lent sketch of his life. 



DTNAMITE-GUN, THE. The value of dynamite 

 and other high explosives in war would be much 

 increased were a practical means in use for pro- 

 jecting bombs, or cartridges charged with such 

 explosives, to considerable distances, as ordi- 

 nary bombs are projected from mortars. The 

 projectiles can not be fired with a charge of 

 powder, for the shock of the detonation of the 

 powder would certainly cause a premature ex- 

 plosion of the cartridge, with the destruction 

 of the gun and great danger to the persons en- 

 gaged in its manipulation. A plan has been 

 devised by Mr. H. D. Winsor, of New York, 

 and the persons associated with him, for apply- 

 ing the expansive force of compressed air or 

 steam under high tension for the discharge of 

 the dynamite projectile, and has been subject- 

 ed, by order of the Government, to experi- 

 mental tests under the direction of Lieutenant 

 E. L. Zalinski. Guns in which the principle 

 may be applied have been in making at the 

 Delamater Iron -Works in New York. The 

 four-inch gun is illustrated in the engraving. 

 It consists of a tube forty feet long and a quar- 

 ter of an inch thick, mounted upon a light steel 

 girder. The latter is trunnioned, and is also 

 pinioned on a cast-iron base, so that it may be 



