324 LECTURES TO SCIENCE TEACHERS. 



disadvantage of being at a distance from the fourth 

 necessary raw material, viz., coal. 



Although the process for making alkali was published in 

 the Annales de Cliimie for the year 1797, it is remarkable 

 that some years elapsed before this process was taken up 

 in England. This may be partly accounted for by the fact 

 that as war was then raging, communication between the 

 two countries was almost entirely cut off, but perhaps 

 especially because of the high war- duty on salt which 

 existed up to the year 1823. 



In the year 1819 Mr. Charles Tennant, of Glasgow, 

 erected sulphuric acid chambers in that city for the 

 purpose of decomposing salt and manufacturing soda on 

 Leblanc's process, and in the year 1821 Mr. Losh, of 

 Newcastle, erected works at Walker on the Tyne for the 

 manufacture of soda crystals, which were then obtained 

 from kelp and sold at 60/. per ton. Mr. Losh made use 

 of a weak brine-spring for the purpose of obtaining his 

 salt, having been permitted to employ this free from salt- 

 duty, but the extent of his works was naturally limited 

 by the use of this brine instead of the solid salt. At 

 this time the price of sulphur was 11. per ton, the duty 

 being remitted ; and the cost of nitrate of potash was 321. 

 per ton ; the continuous sulphuric acid process, which, as 

 I mentioned in my previous lecture, had been devised by 

 Chaptal, being at this time employed. 



The year 1823 may really be considered the one in which 

 the alkali trade began, inasmuch as in that year, the duty 

 having been taken off salt, Mr. James Muspratt commenced 

 the erection of works at Liverpool, at once adopting Leblanc's 

 process. 



Another discovery of enormous commercial importance 

 was that of the bleaching action of chlorine by Scheele 

 in 1774, and the subsequent application by Berthollet 

 of the bleaching action of the hypochlorites of potash 

 and lime. In 1787 Professor Copeland of Aberdeen brought 

 over Berthollet's process to Scotland, and in concert with 

 the Duke of Gordon commenced works in Aberdeen 

 for the manufacture of chlorine in large Woulff s bottles, 

 and applied the process successfully to bleaching calicoes. 



Up to this time the bleaching of all the cotton goods 

 made in Lancashire was effected by exposure to sunlight 



