INDUSTRIAL PROGRESS DURING THE YEAR 1873. cxxvii 



whether it will remunerate the growers to continue its pro- 

 duction in the future. Last year it is estimated that over 

 one fourth of the total quantity of this dye-stuff employed 

 was the artificial product. There can remain no doubt that 

 the industry which" has developed so greatly within the past 

 year or two will in the near future entirely extinguish the 

 growing of the madder in Europe at least, thus turning thou- 

 sands of acres of land and laborers into other and more prof- 

 itable channels of production. 



In the Soda manufacture, the past year has largely wit- 

 nessed the introduction of the new ammonia process, which 

 bids fair to make in time as radical a change in this vast and 

 leading chemical industry as the one above noted. In many 

 parts of Germany and in Switzerland soda-works upon the 

 new plan are in operation, some of them producing as much 

 as fifteen tons per day. The new process possesses the one 

 great advantage over the Leblanc, so universally in use up 

 to the present time", in that the conversion of the common salt 

 into soda is direct. The whole process depends upon the 

 treatment of a strons; solution of common salt with bicar- 

 bonate of ammonia ; the resultant of the reaction being the 

 precipitation of the sodium as bicarbonate, and the formation 

 of a chloride of ammonium. From this last, the ammonia is 

 again recovered for a second operation by treatment with 

 caustic lime, w^hile the sodium bicarbonate is converted into 

 the simple carbonate the soda- of commerce by heating, 

 the carbonic acid evolved being employed to unite again 

 with the regained ammonia. 



The opinion of the judges at the late Vienna Exposition, 

 of which Professor A. W. Hoffmann w^as president, was to the 

 effect that the new process which has grown into a flour- 

 ishing industry almost before its existence is generally known 

 w^as destined in the near future to entirely exclude that 

 of Leblanc. 



In the field o^ Illumination^ the year IS^S may point to 

 several decided advances. The process of Tessie du Mothay, 

 which during the past few years has been the topic of so 

 much and varying criticism, has been very thoroughly tested 

 in Vienna for the illumination of depots and other large pub- 

 lic buildings, and with most excellent effect. The unfavora- 

 ble comments made upon the oxygen illumination process, 



