JAMES SHANKS 209 



of lime was recovered by running it into a 

 tank, adding to it a quantity of hot water 

 and lime by preference to milk of lime, to 

 neutralize the acid, and adding a further 

 quantity of lime to precipitate the oxide of 

 chromium, and an excess to combine with 

 the chromic acid obtained in the calcination 

 of the precipitate, for the precipitate is 

 collected in a drainer, and afterwards mani- 

 pulated in a furnace at low redness, with a 

 free admission of air ; chromate of lime is 

 thus recovered ready to perform its part in 

 the repetition of the original process in the 

 production of chlorine. 



For this patent a medal was awarded 

 Shanks by the Jury of the International 

 Exhibition, ',1862, and Dr. Hofmann, the 

 reporter, adverts to it in his report. He 

 says : " The reaction between hydrochloric 

 acid and chromate of potassium is well 

 known, chloride of potassium, chromic 

 chloride and water being formed with liber- 

 ation of chlorine. 



M. Peligot and M. Gentele have recom- 

 mended this process for the preparation of 

 chlorine upon a large scale, but unless there 

 be a demand for the chromic chloride the 

 reaction would probably prove too costly. 



