256 ANNUAL EEPOET SMITHSONIAN INSTITUTION, 1908. 



reached a productive stage, and it was recognized that the possibility 

 of obtaining soda independently of the Leblanc process would break 

 up the whole continuity of this great chemical industry. It was still 

 protected, however, by the close dependence on it of the production 

 of hydrochloric acid and from this the making of chlorine by the 

 sulphate process, and by the advantages offered by the soluble product 

 of its raw soda in the preparation of caustic soda. In truth, these 

 two circumstances prolonged the life of the Leblanc process for sev- 

 eral decades and are responsible for the fact that even yet it has not 

 entirely disappeared. 



Toward 1860, almost simultaneously with the development of a 

 commercial process for the production of soda by ammonia, came the 

 inauguration of the potash industry at Stassfurt, which was founded 

 on the fortunate discovery of the deposits of salts there, under the 

 fertile influence of Liebig's wonderful researches. 



To the preparation of potassium chloride from carnallite and 

 sylvinite soon was added the preparation of bromine, of potassium 

 nitrate by the use of sodium nitrate, and the manufacture of potash 

 by the Leblanc process, without any danger here of a concurrent 

 process with ammonia. Finally, a successful process was developed 

 for the utilization of part at least of the magnesium compounds which 

 were present in the salt deposits, although the successful extraction 

 of all the magnesium chloride made in the potassium industry is 

 to-day still in the category of unsolved problems. 



The year 1870 saw the rejuvenation of the century-old industry 

 of oil of vitriol, the fuming sulphuric acid, whose small content of 

 sulphuric anhydride no longer sufficed for modern needs. 



In place of the product obtained by distilling vitriolic schists came 

 synthetic sulphuric anhydride, prepared by the catalytic combination 

 of sulphurous anhydride and oxygen, and the pyrosulphuric acids. 

 This new process of manufacture was to influence and transform the 

 whole sulphuric acid industry to a great extent. It was possible to 

 apply it to advantage more than a quarter of a century later, when 

 the modern contact processes appeared. 



The last two decades of the nineteenth century were characterized 

 by the development and application with exceptional rapidity of elec- 

 tro-technics. In the field of chemistry, this new phase of industry 

 voiced itself in the development of electrolytic methods of operation. 

 In the field of electro-metallurgical processes, the most important of 

 which are the preparation of aluminum and the electrolytic refining 

 of copper, which are closely followed by the manufacture of calcium 

 carbide and carborundum, the question of the electrolytic decomposi- 

 tion of alkaline chlorides has been a most warmly discussed problem. 

 The difficult problem of preparing membranes which are more sensi- 

 tive, and at the same time more resistant, was solved almost simul- 



