CHAPTER I. 



Discovery and Manufacture of Cyanamid. 



The problem of the artificial fixation of atmospheric nitro- 

 gen has engaged the attention of scientists for the greater part 

 of a century. The rapid growth of the fertilizer industry that 

 has attended the development of agricultural science, and the 

 great increase in the number and extent of chemical industries, 

 during the past fifty years, have emphasized the necessity for 

 artificial methods of maintaining and increasing the world's 

 stock of combined nitrogen. One of the influences that stim- 

 ulated immediate action was the introduction in 1887 by 

 MacArthur and Forest, and at about the same time independ- 

 ently by Siemens & Halske, of Berlin, of the cyanide process 

 for leaching gold and silver from their ores. This discovery 

 produced a strong demand for cyanides, which had hitherto 

 been used to the extent of only a few hundred tons a year, 

 principally in the dye-industry and to a smaller extent in 

 electroplating. 



Attempts had been made early in the nineteenth century to 

 bring about the direct synthesis of cyanogen from atmospheric 

 nitrogen and carbon. Among other processes, that worked 

 out in 1847 by Bunsen and Playfair, in which barium car- 

 bonate was heated in an atmosphere of pure nitrogen, seemed 

 promising, but did not prove to be commercially successful. 

 The introduction of the electric furnace in 1894 by Moissan 

 and by Willson, for the production of carbides on a large 

 scale, afforded a new instrument for further research. Siemens 

 and Halske, among others, at once adopted the use of the elec- 

 tric furnace for the working out of the problem of nitrogen fixa- 

 tion. In 1895, they worked on the process of Prof. H. Meh- 

 ner, which consisted in fusing a mixture of sodium carbonate 

 and carbon and conducting nitrogen through the hot mass. In 

 the same year they took up the process of Prof. Adolph Frank 

 and Dr. Nicodem Caro, which consisted in subjecting a mix- 



