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PRINCIPLES OF CHEMISTRY 



with the sodium carbonate, at a white heat, carbonic oxide and vapours 

 of sodium are disengaged, according to the equation : 



On cooling the vapours and gases disengaged, the vapours condense 

 into molten metal (in this form sodium does not easily oxidise, whilst in 

 vapour it burns) and the carbonic oxide remains as gas. 



Here are the simple means by which metallic sodium may be obtained. 

 An iron tube, about a metre long and a decimetre in diameter, is made 

 out of boiler plate. The pipe is cemented into a furnace having a strong 



FIG. 71. Manufacture of sodium by Deville's process, 

 soda, charcoal, and chalk. 



A C, iron tube containing a mixture of 

 B, condenser. 



draught, capable of giving a high temperature, and the tube is charged 

 with the mixture required for the preparation of sodium. One end of the 

 tube is closed with a cast-iron stopper A with clay luting, and the other 

 with the cast-iron stopper C provided with an aperture. On heating, first 

 of all the moisture contained in the various substances is given off, then 

 carbonic anhydride and the products of the dry distillation of the charcoal, 

 then the latter begins to act on the sodium carbonate, and carbonic oxide 

 and vapours of sodium appear. It is easy to observe the appearance of 

 the latter, because on issuing from the aperture in the stopper C they 

 take fire spontaneously and burn with a very bright yellow flame. The 

 pipe of the condenser is then introduced into the aperture C, compelling 

 in this way the vapours and gases formed to pass through the condenser 

 B. This condenser consists of two square cast-iron trays, A and A', 

 Fig. 72, with wide edges firmly screwed together. Between these two 

 trays there is a space in which the condensation of the vapours of 

 sodium is accomplished, because the thin metallic walls of the condenser 



