TECHNICAL CHEMISTRY. 323 



The report gives a full description of the various processes 

 which constituted Leblanc's invention ; these consisted of 



(1) The decomposition of the common salt (NaCl) by- 

 means of sulphuric acid (H 2 S0 4 ), and the consequent pro- 

 duction of sulphate of soda (Naj30 4 ), with evolution of 

 hydrochloric acid gas (HC1) ; 



(2) The decomposition of the sulphate of soda or salt- 

 cake (Na 2 S0 4 ), by means of chalk and coal, and the con- 

 sequent production of black-ash, consisting essentially of a 

 mixture of soluble carbonate of soda (Na 2 CO 3 ), and insoluble 

 calcium monosulphide (CaS); 



(3) The separation of the constituents of the last product 

 by lixiviation with water and the preparation of the soluble 

 carbonate of soda. 



This process elaborated by Leblanc before the time of the 

 French Revolution is in fact that which is now employed 

 in all the alkali-works in the world without having under- 

 gone any material alteration. The commissioners say in 

 their report : " Citizens Leblanc, Dize", and Shee were 

 the first who submitted to us particulars of their process, 

 and this was done with a noble devotion to the public 

 good. Their establishment had been formed some time 

 previously at Franciade ; but the consequences of the 

 French Revolution and of the war which followed having 

 deprived them of funds, the works were suspended, and for 

 some months past the manufactory has become a national 

 establishment and was successfully at work in the year 

 1794." The operations however did not proceed satisfac- 

 torily, the quantity of soda turned out was smaller than 

 had been expected, the operations were discontinued, and 

 Leblanc and his partners applied for and received assistance 

 from the English Government. It is sad to have to relate 

 that the man who thus originated a world-wide industry did 

 not benefit from his discoveries, but died in a French 

 asylum for paupers. 



The establishment of numerous alkali-works in France 

 was the natural result of this discovery; many of these 

 were situated at Marseilles, the seat of the French soap 

 trade, and conveniently placed for obtaining three of the 

 necessary raw materials : (1) Sulphur, imported from 

 Sicily ; (2) salt, obtained by the evaporation of salt-water 

 by the sun's heat; (3) limestone. It had however the 



