SULFURIC ACID. 27 



the contact substance, that of reducing the platinum by the use of 

 formic acid salts. This keen discovery of Winckler's brought at once 

 into existence a new industry, that of the synthetic manufacture of 

 fuming sulfuric acid. A number of works immediately adopted 

 Winckler's process, among them first the Badische Anilin- und Soda- 

 FabriJc, while the monopoly of Stark in Bohemia was broken. The 

 whole industry therefore owes Winckler a debt of gratitude for this 

 advance in technology. 



Further work in this field was wholly under Winckler's influence. 

 This is true of the patent secured ten years later by Haenisch and 

 Schroeder, who replaced pure oxygen by atmospheric air, retaining, 

 however, the use of pure sulfur dioxid, and compensating for the dilu- 

 ting influence of the nitrogen by carrying on the reaction under pressure, 

 in order, as the patent reads, that the molecules of the gases may be 

 brought closer together. This process also was put into practical appli- 

 cation in the Badische Anilin- und Soda-Fabrik. 



Messel and Lunge proposed a method of obtaining a stoichiometric 

 mixture and at the same time excluding the atmospheric nitrogen by 

 burning the pyrites with pure oxygen. All these processes were unsuited 

 by their very nature to compete with the lead chamber process and were 

 necessarily confined to the manufacture of the fuming acid. Never- 

 theless attempts at the solution of the larger problem were by no means 

 wanting; little, however, regarding them made its way to the notice of 

 the public. Winckler especially published nothing regarding his new 

 work along this line, so that it only became known last year, through 

 the striking lecture of Lunge and Winckler in Hannover on the devel- 

 opment of sulfuric acid manufacture, that at his instance it had been 

 found possible at the Mulden works to convert from two thirds to 

 three fourths of the sulfur dioxid in the pyrites-burner-gases into sul- 

 furic acid. 



Purification of the Gases. 



The solution of the problem of the complete conversion of the 

 burner-gases into sulfuric acid remained unsolved, and indeed at that 

 time, as far as was known, theoretically or practically, was unsolvable. 

 Nevertheless, as I attacked the problem at the Badische works, it was 

 chiefly theoretical considerations which made the possibility of attain- 

 ing this great goal seem not absolutely out of the question. 



It is well known that in the lead chamber process there is always 

 an excess of six volumes per cent, of oxygen in the gases as they leave 

 the chambers. In working with pyrites-burner gases under similar 

 conditions, there would naturally always be this excess of oxygen, 

 whatever contact-method was employed for making the acid, and it 

 could not be understood why in spite of such an excess of oxygen the 

 reaction should not proceed quantitatively. The question was tested 



