254 ALKALIES. 



2. MODES OF OBTAINING. The same as those described for po- 

 tassium ; only the decomposition of soda is more difficult, requir- 

 ing a higher voltaic power, and in the process by the furnace, a 

 greater degree of heat ; a mixture of potash and soda is more easily 

 decomposed, and affords an alloy of the two metals. 



Dry muriate of soda or chloride of sodium is decomposed by po- 

 tassium, with the aid of heat, and sodium is evolved ; it is done in an 

 iron tube. 



3. PROPERTIES. 



(a.) Extremely similar to those of potassium. 



(b.) Rather more solid at the common temperature under naptha, 

 brilliant like silver, and quite as white. 



(c.) Very malleable ; by pressure of a platina blade, a globule T V 

 or y'g- of an inch in diameter, is made to cover of a square inch, and 

 this property does not diminish even when it is cooled down to 32. 



(d.) Several globules, by strong pressure, unite into one, and it is 

 therefore capable of being welded at the common temperature, while 

 iron and platinum require full ignition. 



(e.) It merely floats on ivater; the sp. gr. at 59 Fahr. is sup- 

 posed to be 0.972, water being 1. 



(f.) Less fusible than potassium ; softens at 120, is perfectly 

 fluid at 180 or 200, and readily melts under naptha. 



(g.) J^aporizable, but at what exact temperature is unknown, for 

 it does not rise in vapor at the fusing point of plate glass, but is dis- 

 tilled at an intense heat. 



(A.) Tarnished by common air, but not by air artificially dried, un- 

 less heated in it. 



f i.) Heated to fusion, it burns with scintillations and white flame. 

 ) On ivater, it melts, appears like a globule of floating silver, 

 and wastes rapidly away, but without emitting light, unless the water 

 be hot, when it scintillates and flames ; there is no combination of the 

 sodium with the hydrogen evolved by the decomposition of the wa- 

 ter, on the surface of which it has a rapid motion, owing to the causes 

 mentioned under potassium. It burns in chlorine gas with bright red 

 scintillations, and muriate of soda is the result. When plunged be- 

 neath it, it decomposes water with violent effervescence, and a loud 

 hissing noise ; soda is formed, and hydrogen evolved, but there is no 

 luminous appearance. On moistened paper, or in contact with a 

 small globule of water, as there is nothing to carry off the heat, the 

 sodium usually inflames. The action on alcohol and ether, is the 

 same as that of potassium. In the action of sodium on the oils, 

 and on naptha, on sulphur, and phosphorus, on mercury and sev- 

 eral other metals, there is almost a perfect similarity with the ac- 

 tion of potassium. The soaps are of a darker color, and less solu- 

 ble ; the combination with sulphur, (effected as in the case of potas- 

 sium in close vessels filled with the vapor of naptha,) is attended with 



