518 Intelligence and Miscellaneous Articles. 



which have the closest possible resemblance to those of the meteoric 

 iron of Texas. It also shows numerous large and small intermixed 

 grains of sulphuret of iron, which during the corrosion gave off the 

 odour of sulphuretted hydrogen. Some chemical experiments made 

 by the author have proved that it contains nickel : the exact com- 

 position will be yielded by its analysis, which Rammelsberg has 

 imdertaken. — Bericht d. Academ. d. Wissensch. zu Berlin, 1851, 

 p. 104-106. 



METHOD OF OBTAINING OXYGEN FROM ATMOSPHERIC AIR. 

 BY M. BOUSSINGAULT. 



Lavoisier resolved atmospheric air into its constituents by keeping 

 a confined portion for twelve days in contact with mercury heated 

 nearly to its boiUng-point. Boussingault has attempted to use baryta 

 for the purpose of extracting the oxygen from the atmospheric mix- 

 ture in larger proportion, The method is simjile ; the air is con- 

 ducted over pieces of baryta at a dark red heat until it has become 

 converted into peroxide of barium ; the oxygen is subsequently again 

 expelled by the application of a more intense heat. The moisture 

 and carbonic acid usually present in the air do not materially interfere 

 with the process. The baryta, however, contained so much alumina 

 and silica, that after repeated use it became caked, and hence no 

 longer of any use. Pure baryta was free from this inconvenience. 

 According to Boussingault, on the large scale, on using 10 kilo- 

 grammes of baryta, which absorb 730 litres of oxygen, and should 

 again part with it, 600 litres is the quantit}'' always obtained in 

 practice. Hence with furnaces in which 100 kilogrammes of baryta 

 distributed in 8 to 10 tubes can be heated at once, from 24,000 to 

 30,000 litres of oxygen may be produced in twenty-four hours. — 

 Comptes Rendus, vol.xxxii. pp. 266, 267. 



ON GILDING PORCELAIN. 



In Paris a method of gilding porcelain is at present practised 

 which is very economical, as the gold can be applied in very thin 

 layers. The gilding, however, is not very permanent. The me- 

 thod consists in precipitating the gold from its solution in aqua 

 regia by protonitrate of mercury, and then mixing it with basic nitrate 

 of bismuth. In other respects the usual proceeding is adopted. To 

 render the gilding more durable, M. Grenon recommends a layer to 

 be previously burnt in ; this is then polished, and a second thin layer 

 applied upcm it in the above manner. — Gewerbeblatt aus Wiirtemberg, 

 1851, No. 6, pp. 46, 47. 



SEPARATION OF THE PROTOXIDE AND PEROXIDE OF COPPER. 

 BY H. ROSE. 



The protoxide of copper is not precipitated from its solution in 

 hydrochloric acid by carbonate of baryta. Hence it is a powerful 



