September 6, 1895.] 



SCIENCE. 



295 



cult to recognize instant practical value in 

 them. The numerous naphthyldiamine, 

 amido-naphthol and dioxynaphthaliue sul- 

 phonic acids were patented, not indeed 

 because a special technical interest was 

 claimed for them, but only because they 

 were new and it was scarcely possible at 

 once to determine whether they would be 

 applicable in one direction or another." 



In no direction has the application of 

 the methods in the lai'ger way, either in the 

 laboratory or in the works, given richer 

 yields in new material than in the varied 

 uses of the electric current in chemical work. 

 It has led to the production of new com- 

 pounds or has increased the means for pro- 

 duction of old ones, and through it additions 

 are constantly being made to the store of 

 material of such composition and properties 

 that they mu.st inevitablj^ lead to further 

 new discoveries or the establishment of new 

 principles or laws. It has added greatly to 

 our knowledge of the reactions of oxidation 

 and reduction and has made new applica- 

 tions of those phenomena possible. In this 

 connection we may refer to the processes 

 of Hoepfner and of Siemens and Halske for 

 the extraction of copper from its solutions, 

 wherebj', as the metal is removed from the 

 solution at the cathode, the reduced salts 

 are oxidized at the anode, and the solutions 

 thus brought to the higher state of oxida- 

 tion are ready for use on new portions of 

 ore.* Similar reactions occur in the new 

 process of Lowenherz for the production of 

 sodium persulphate, a compound new to 

 chemistry and resulting from the applica- 

 tion of electricity on a scale more extended 

 than is usually employed for laboratory 

 work. Sulphuric acid and sodium sulphate 

 solutions, separated bj^ a porous diaphragm 

 are electrolj'zed with the anode immersed 

 in the sodium sulphate . The resulting com- 

 pound is comparatively unstable, yielding 

 up its oxygen with the production of acid 



*Zeitsclir)ft fur Angewandte Chemie, 1893. 



sodium siilphate. And since this latter may 

 readily be neutralized by sodium carbonate, 

 the new compound is recommended for all 

 uses in which oxidation may be applied.* 



With the production of hypochlorites and 

 the chlorates we are already familiar. It 

 grows rapidly with the cheapening of arti- 

 ficial power or the iitilization of natural 

 power, until eventuallj^ the world's demand 

 for them must be covered by materials from 

 this source. The reaction necessary to this 

 is further utilized in the production of such 

 compounds as chloral, iodized phenol and 

 other similar substances. f 



In the field of reductions reference may 

 with interest be made to the late discov- 

 eries of Gattermann and the color works of 

 Fr. Bayer & Co., that electrolysis is readily 

 applied to the production of a large number 

 of compounds not heretofore produced tech- 

 nically but for which technical uses con- 

 stantly exist. Their earlier discovery of 

 the application of electrolysis to the reduc- 

 tion of nitrobenzene to amido-phenol with in - 

 termediate production of phenyl-hydroxy- 

 lamine finds wider application than they at 

 first supposed and will doubtless constitute 

 the starting point of a new line of sj'nthesis 

 of the carbon Compounds.! This reaction 

 is similar to that of zinc dust in alkaline 

 solutions, preferably in alcohol containing 

 calcium chloride whereby, as noticed by 

 Wohl and Bamberger, phenyl-hj'droxyla- 

 mine is produced instead of the aniline pro- 

 duced by the reduction with acetic acid and 

 iron. 



The electrical smelting furnace has opened 

 up a wide field of experiment and investi- 

 gation as fascinating as it is new, and it is 

 to be expected that many additions will be 

 made to the list of new substances through 

 its use. The increased production of chro- 

 mium and the crystallization of carbon by 



•^ Zeitsclirift fur AngeTvandte Chemie, 1895, 349. 

 fChem. Zeit., XIX. 

 JChem. Zeit., XIX., 1111. 



