198 Britain's Heritage of Science 



J. Hemming in 1838, and worked on a small scale in White- 

 chapel. Muspratt also had given it a trial at Newton, but 

 abandoned it again. After protracted investigations, the 

 Belgian chemist, Ernest Solvay, overcame the main manu- 

 facturing difficulties, and took out a patent in 1872. In the 

 meantime, Ludwig Mond (1839-1909) had settled in England 

 at the age of 23, and had gained practical experience with the 

 Leblanc process while occupied in some chemical works at 

 Widnes. Recognizing the possibilities of the ammonia-soda 

 process, he obtained a licence from Solvay, and in partnership 

 with Sir John Brunner, founded in 1873 the great chemical 

 works near Northwich. Further difficulties were experienced, 

 but these were gradually overcome, mainly by improved 

 devices for recovering the ammonia, on which the commercial 

 success of the process largely depends. 



A third method of making alkalies became possible when 

 the introduction of dynamo-machines provided an easy 

 means of obtaining strong electric currents. Various electro- 

 lytic processes were then devised and patented. In the 

 Castner-Kellner method, used extensively in this country, 

 the kathode of the electrolytic trough is formed by mer- 

 cury, and the sodium is transferred by the current from the 

 solution to the mercury with which it amalgamates; by a 

 self-acting arrangement the amalgam is removed before it 

 becomes strong enough to act on the water. That action is 

 ultimately allowed to take place in another vessel, where a 

 solution of caustic soda is formed. 



Among the chemical engineers of the alkali trade, Henry 

 Deacon (1822-1876) and Walter Weldon (1832-1885) also 

 hold distinguished places. They both successfully invented 

 independent and quite different processes for the manu- 

 facture of chlorine, which are still in use, though partly super- 

 seded by electrolytic methods. An important improvement 

 in the manufacture of sulphuric acid was made by J. Glover, 

 who, in 1866, introduced the important de-nitrating tower. 



In the early forties of last century a determined effort 

 to promote chemical research was made in London. With 

 the support of Faraday and Brande, it was at first intended 

 to attach the necessary laboratories to the Royal Institution, 

 but on closer consideration the available space was found to 



