474 Miscellaneous Intelligence. 



Upon evaporating the acid, and heating it to redness, it recovered 

 its precipitating power, but gradually lost it again by a day's 

 repose. The cause of this difTerence escaped detection ; it evidently 

 does not depend upon a difference of oxidation. " May it not be 

 supposed," says Berzelius, "that there exists a chemical combina- 

 tion of phosphoric acid with water, which is not formed until some 

 time after solution, and which is incapable of precipitating albu- 

 men ?'* — Annates de Chimie, xxxvi. 110. 



16. Economical Preparation of Beutoxide of Barium. — This 

 process is due to M. Quesneville. Nitrate of baryta is to be put 

 into a luted earthenware retort, to which a tube is to be attached 

 for the purpose of conveying the liberated gases to a water-trough. 

 The retort is to be gradually heated to redness, and retained at that 

 temperature as long as nitrous acid and azotic gas pass over ; the 

 evolution of these substances indicates that nitrate of baryta still 

 remains to be decomposed, but the instant that pure oxygen gas 

 passes off, the fire is to be removed and the retort cooled. The 

 product of this decomposition is a peroxide of barium ; it falls to 

 pieces in water, without producing heat, disengages oxygen when 

 boiled with water, and is reduced to a protoxide by a strong heat. 

 When acted upon by sulphuric acid, no nitric acid was evolved ; 

 and when subjected to nitric acid, no nitric oxide was produced. 

 The production of this peroxide is easily understood, for the prot- 

 oxide formed by the decomposition of the nitrate being in contact, 

 at a red heat, with a large quantity of oxygen in a nascent state, 

 combines with it, and is retained, unless the heat be so high as to 

 decompose W.^—Annales de Chimie, xxxvi. 108. 



The decomposition and effect are precisely the same as those 

 lately pointed out by Mr. Phillips as occurring with potassium when 

 the nitrate of potash is decomposed by heat. — Seep. 483 of the last 

 volume of this Journal. 



17. Preparation of Aluminum — Chloride of Aluminum. — Accord- 

 ing to the accounts published, the following process has succeeded in 

 the hands of M. Oersted, in decomposing alumina and evolving the 

 base aluminum. Pure alumina is to be heated to redness, and then 

 well mixed with pulverized charcoal ; the mixture is to be placed in 

 a porcelain tube^ and being heated to redness, is to have dry chlorine 

 gas passed over it ; the charcoal reduces the alumina, the base 

 combines with the chlorine, and oxide of carbon is formed. The 

 chloride of aluminum is soft, crystalline, and evaporates at a tem- 

 perature a little above 212° Fahrenheit : it readily attracts moisture 

 from the atmosphere, and becomes hot when water is added to it. 

 Being mixed with an amalgam of potassium, containing much of 

 the latter metal, and immediately heated, chloride of potassium is 

 formed, and the metallic base of the alumina combines with the 

 mercury. The amalgam quickly oxidises by exposure to air ; but, 

 being heated out_of contact with the atmosphere, the mercury is 



