September 6, 1895.] 



SCIENCE. 



287 



and much of his inspiration was drawn 

 from them. It was an incident similar to 

 that ah'eady described that brought Dumas 

 to the reaction whereby hydrogen sulphide 

 may be oxidized to sulphuric acid. He 

 found the walls of one of the bath rooms at 

 Aix les Bains covered with crystals of cal- 

 cium sulphate, which could have no other 

 source than the vapors liberated fi'om the 

 hot water. No trace of sulphuric acid 

 could be found in the atmosphere of the 

 room. The portieres of the room soon 

 acquired an acid reaction, which proved 

 to be due to sulphuric acid. Dumas con- 

 cluded that the combination of hydrogen 

 sulphide with oxygen had occurred upon 

 the wall itself, the porous surface ex- 

 ercising an influence similar to that of 

 platinum black upon hj^drogen and oxygen. 

 A subsequent investigation showed that 

 when air steam and hydrogen sulphide are 

 passed over porous substances at from 40° 

 to 50° C, and still better at 80° to 90°, sul- 

 phuric acid is quickly formed without in- 

 intermediate formation of sulphurous acid 

 or separation of sulphur. 



Similar instances are set forth by Hoff- 

 mann* — who seems to have recognized the 

 value of the influences we here have in 

 m^ind — in his necrological address upon 

 Liebig, whose well-known devotion to the 

 industries and their advancement is so fa- 

 miliar and interesting. Hoffmann says : 

 " 1^0 branch of chemical industry has failed 

 either directly or indirectly to receive bene- 

 fit from Liebig's works." He calls atten- 

 tion to the study of the fat and acetic acid 

 industries, and declares that the key to their 

 peculiar operations is of his making, that 

 the preparation of the prussiates and ful- 

 minates, the manufacture of the cyanides, 

 the production of the silver mirror, were the 

 result of Liebig's work. His interest in the 

 problems of agriculture and of the nutrition 



* Hoffmann, Berichte der Deutschen Chemisoheu 

 Gesellschaft, VI., 647. 



of plants and animals, of physiology and 

 pathology, led him not only to the develop- 

 ment of many new industries, but to the es- 

 tablishment of many of the truths of science 

 as well. His method for the production of 

 artificial foods and concentrated animal ex- 

 tracts were not the smallest of his contribu- 

 tions to the industry, and the possibilities 

 of their value and wide application in turn 

 led to further investigation. Meyer,* quot- 

 ing from Hoffmann, saj^s: "If we could 

 hold to view all that Liebig has done for 

 the well-being of the human race in the in- 

 dustries, in agriculture or in the promotion 

 of health, one can scarcely declare that any 

 other scholar of his time has left a richer 

 legacy to mankind." 



And what Hoffmann has said of Liebig 

 is also applicable to himself, for in many re- 

 spects he rivalled Liebig in his intelligent 

 comprehension of commercial and industrial 

 needs and their value in suggesting new 

 and fruitful lines of woi'k. No question 

 could be proposed to him that had not for 

 him some germs of useful thought, and it 

 was the utilization of such possibilities as 

 came to him in this way that made him 

 great. His geniu.s for this will be illus- 

 trated in connection with the incidents in 

 the coal tar color industry which show the 

 relation of that great branch of human en- 

 deavor to the subject in hand. 



It seems to make little difference to which 

 branch of chemical work we turn for illus- 

 trations of the ideas just presented. The 

 enormous losses suffered by Italy and 

 France by the diseases of the silk worm, the 

 deterioration of the wines and the diseases 

 of farm animals, made demands upon the 

 genius of Pasteur, and through his brilliant 

 work and magnificent results attention has 

 been directed to the field of bacteriology 

 and fermentation, and almost a new science 

 has been built upon it. What a mass of 

 material has through this one branch of 



* Geschiclite der Chemie, 231. 



