200 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



salt is a powerful oxidizing agent, and produces greenish 

 precipitates with metallic solutions. Bull. Soc. Chwiiqice, 

 181 5, October 5. 



IMPEOYEMENT IN THE AMMONIA-SODA PEOCESS. 



The following improvement in the ammonia process for 

 the manufacture of soda has been patented in England. 

 The solution of chloride of ammonium formed is mixed with 

 carbonate of magnesia and distilled, and the carbonate of 

 ammonia, which passes over, is again used in the manufact- 

 ure of soda. The solution of chloride of magnesium remain- 

 ing, which also contains some chloride of sodium, originally 

 present with the chloride of ammonium, is concentrated, and 

 the chloride of sodium removed from time to time as it crys- 

 tallizes out. What remains is then calcined with the forma- 

 tion of hydrochloric acid and magnesia. The latter is recon- 

 verted into carbonate by the gaseous products of combustion 

 from the furnace. The separation of the chloride of sodium 

 before the calcining is important, as otherwise the chloride 

 of magnesium will not be decomposed by heat alone. A 

 partial decomposition of the chloride of magnesium, however, 

 is said to be more favorable to the conversion into carbonate 

 than complete decomposition. 5 (7, XXXVIII., 1875, 303. 



MANUFACTURE OF SODA FEOM SEA-WEED. 



Herland, in Comjytes Ilendus, calls attention to some de- 

 fects in the treatment of sea-weed for the manufacture of 

 soda, and makes some suggestions for an improvement of 

 the process. He remarks that in the ordinary method the 

 weeds destined to be calcined are dried on the shore in the 

 open air, involving decomposition and a loss of salts by 

 moisture, and that the process of incineration is itself de- 

 fective. The method by w^hich he proposes to remedy the 

 difficulty is as follows : Place the fresh weed in baskets of 

 iron wire, moved by a turning crane, and steeped in a series 

 of vats containing about fifty kilogrammes of good quicklime 

 per cubic meter, and so placed that it can pass in succession 

 from vat to vat until it is exhausted of its useful salts. The 

 time of steeping in each vat is from forty to sixty minutes. 

 The successive saturated lyes are to be reduced to dryness 

 and. treated with carbonate of potash. This will yield a 



