PROGRESS IN CHEMISTRY. 257 



The use of artificial manures, prepared by mixing refuse animal 

 matters with tetra-hydrooen, calcium phosphate, and nitrate of soda or 

 sulphate of ammonia, first introduced by Liebig, has created a revo- 

 lution in agricultural methods and in the weight of crops obtainable 

 from a given area of soil. The influence of manures on crops has 

 l)een fully studied by Lawes and Gilbert for more than fifty years in 

 their experimental farms at Rothampstead. The most remarkable 

 advances which have been made, however, are due to cheap electric 

 current. The electrolysis of alumina, dissolved in fused cryolite to 

 obtain aluminum, an operation carried out at Schaft'hausen on the 

 Rhine and at the Falls of Foyers in Scotland, the electro deposition 

 of pure copper for electric W'ires and cables, electro silvering, gilding, 

 and nickeling, all these are instances where decomposition of a com- 

 pound by the electric current has led to important industrial results. 

 At present soda and chlorine are being manufactured by the electro- 

 lysis of salt solution contained in rocking trays, one of the electrodes 

 ])eing mercury, by the Castner-Kellner process. This manufacture is 

 ])eing carried on at Niagara, as well as in England. But electricity as 

 a heating agent finds ever-extending application. Henri Moissan 

 (professor at Paris) led the way by utilizing the enormous heat of the 

 arc in his electric furnace, thereb}^ among other interesting reactions, 

 manufacturing diamonds, small, it is true, though none the less real. 

 The use of electricity as a heating agent has received new applications. 

 Phosphorus is now made by distilling a mixture of phosphates of lime 

 and alumina with coke; a new polishing agent has been found in "car- 

 l)orundum," a compound of carbon and silicon produced by heating in 

 an electrical furnace a mixture of sand and coke, and cyanide of 

 potassium, almost indispensable for the extraction of gold from ores 

 poor in gold, is now manufactured b}- heating a mixture of carbon and 

 carbonate of barium in an electric furnace in a current of carbon 

 monoxide. These are but some of the instances in which electricity 

 has been adopted as an agent in eflecting chemical changes, and it 

 may l)e confidently predicted that the earlier years of the twentieth 

 century will witness a great development in this direction. It may be 

 pointed out that the later developments of industrial chemistry owe 

 their success entirely to the growth of chemical theory; and it is 

 obvious that that nation which possesses the most competent chemists, 

 theoretical and practical, is destined to succeed in the competition 

 with other nations for commercial supremacy and all its concomitant 

 advantages. 



