JAMES SHANKS 215 



principle of this method was nothing more 

 than mere filtration. 



The second arrangement was one invented 

 by Clemen t-Desormes. It was principally 

 used in France, Germany, and Belgium. We 

 believe that Muspratt was the only English 

 manufacturer who ever adopted it. Clement- 

 Dsormes' method was to place the black- 

 ash balls in perforated boxes that were 

 suspended in tanks, so that the solution in 

 the tanks, when they were full, just covered 

 the black-ash in the boxes. 



Clment-Dsormes had observed that any 

 substance dissolves more rapidly when placed 

 near the surface of the solution than when at 

 the bottom, the reason being manifest, the 

 more material dissolved the greater the 

 density of the solution, and the denser portion 

 sinking, causing the lighter and less con- 

 centrated to rise and so come in contact with 

 the substance, or if the tank was being 

 regularly supplied with fresh water or weak 

 lye, then the more dense sinking to the 

 bottom was drawn off into another vessel by 

 a pipe from the bottom. 



In some respects this was a great im- 

 provement on the original plant ; it prevented 

 the breaking to so great an extent of the 



