1 54 Scientific JntelUgcnce^ — Chemistry. 



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bromide of calcium remains. Acids disengage bromine. In a word, 

 it has all the characters of chloride of lime. 



Preparation of bromine. — The mother waters which contain it are 

 •educed to a quarter of their volume in iron pots and left several days 



in repose, during which the greater part of tlie chloride of calcium crys- 

 tallizes. The supernatant liquid, after dilution with water, is mixed 

 with sulphuric acid as long as a precipitate ensues. The supernatant 

 fluid is then decanted, and the residuum is subjected to -pressure. 

 All die fluids are united, evaporated to dryness, and the residue dissol- 

 ved ill order to separate a certain quantity of sulphate of lime. The 

 bromine is obtained by treating the solution with sulphuric acid and 

 peroxide of manganese. — Ann. de Chim, Oct. 1829. 



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19. Freparaiion of bromine by M. Hermann from the mother water 

 of the salt spring of Schmebeck. — Twenty pounds of the mother Avater, 

 much concentrated, are distilled with twenty pounds of sulphuric acid 

 of a density about 1.520 the product is about fifteen pounds of hydro- 

 cloric acid. This product saturated witli chalk, is decomposed by 

 sulphate of soda. The liquid separated from the sulphate of lime, 

 is concentrated, and the supernatant mother water is treated with sul- 



and 



Nothing 



disengaged. 



The fluid remaining in the retort, after the distillation of the hy- 

 drocloric acid, and which contained a great excess of sulphuric 

 acid, is saturated with carbonate of magnesia, and the magnesian salt 

 thus formed Is separated by crystallization. The remaining mother 

 water, treated like the })receding5 gives immediately a considerable 



quantity of bromine, — Idem. 



20. Preparation of iodiiret oj azote^ by M. Serullas. — Saturate 

 alcohol at 33^ wnth iodine, filtering or decanting to separate some im- 

 purities, which are always present, and adding liquid ammonia in 

 great excess, stirring the mixture with a tube. Dilute with water, 

 and by repose the ioduret is deposited, so that with care the liquid 

 can be decanted off to the last portion. Wash die remainder well 

 with water and the ioduret remains in the form of a fine powder. 

 The washing by dccantatiou Is most convenient, but it is sometimes 

 necessary to finish with the filter, because the ioduret being extreme- 

 ly divided, a portion of it is very slowly deposited - 



This modification of the process is considered as stated by the 

 author to be incomparably superior to the ordinary, especially as U 



