116 Notice of some Recen t [Feb . 



0-065. From which it appears that in mixture they retain 

 the same volatility as when separate. Chloride of lithium 

 is more volatile than either of the other chlorides. 



1-134 chloride of potassium heated in a large crucible, 

 18 lines deep, lost in the first quarter of an hour 0*026 grm. 

 In the second quarter 0*0265 



1.101 grms. chloride of lithium in the same circum- 

 stances lost in the first quarter ------ 0*017 



In the second quarter ------- 0*013 



1-100 grms. of chloride of sodium in the first 



quarter 0*007 



In the second quarter ------- 0*009 



The relative volatilities, therefore, of these salts, begin- 

 ning with the most fixed, is chloride of sodium 1, chloride 

 of lithium 1J, chloride of potassium 3J, in a deep crucible, 

 but in a shallow crucible the proportions are different, the 

 volatility of the chloride of sodium being represented by 1, 

 and that of chloride of potassium hj2^,(Pogg. Ann. xxxi.) 



Manufacture of Artificial Soda. — The calcined sulphate of 

 soda is converted into sulphuret of sodium, by heating it 

 with pulverized charcoal. The sulphuret is dissolved, and 

 oxide of copper added to the hot liquid. The liquid is 

 evaporated after filtration until its spec. grav. be 1*41 or 

 1*48. Then, on allowing it to remain from 24 to 28 hours, 

 the undecomposed sulphate of soda crystallizes. The super- 

 natant liquid is evaporated to dryness. By this process, 

 for every 100 parts of sulphate of soda, 65 of caustic of 

 soda are obtained. It may be converted into carbonate by 

 heating with charcoal. 



Metallic copper, as well as its oxides, can separate the 

 sulphur from the sulphuret of sodium, but in general the 

 protoxide is preferable. To procure this oxide, metallic 

 copper is to be heated to redness, and plunged into water 

 containing in solution 0*02 of nitrate of soda from Chili. 

 The sulphuret of copper, which is the product of this pro- 

 cess, mixed with - 6 of sulphur in powder is easily converted 

 into sulphate by heat. These processes are followed at 

 Hof., according to Prukkner, (Annal de Schweigger, b. vii.) 

 Separation of the Oxide of Cobalt from Oxide of Nickel, 

 {Ann de Chim. lvi. 333.) — M. Persoz separates these oxides 

 by dissolving them in nitrate or muriatic acids, adding as 



