On ihe Decomposition of the Alkalis. «H 



** In about half an hour from the moment at which the 

 •potash is fused, the disengagement of hydrogen ceases, and 

 the operation is concluded. 



<e When the furnace is quite cold, the safety tube is taken 

 away, and the extremity of the gun-barrel is closed by a 

 plug. In order to extract the metal, the gun-barrel is cut 

 at the commencement of the part which has served for a 

 refrigerant, and the metal (potassium) presents itself in the 

 form of small brilliant laminae, adhering to the sides of the 

 gun barrel : the greatest quantity is found close to the re- 

 frigerant ; another portion is not condensed until it is very 

 close to the plug of the safety tube: this last portion ad- 

 heres very slightly to the gun-barrel, and the least effort is 

 sufficient to detach it : it is even partly oxidized by air ad- 

 mitted during; the cooling of the furnace : and when the 

 whole is received over naphtha, the oxidized part is de- 

 tached in lamince, and exposes to view a white and brilliant 

 metallic surface. 



" As to the portion of potash condensed nearer the fur- 

 nace, it must be detached by means of a sharp chisel, and 

 in the largest pieces we can possibly break off; for if it be 

 in small molecules it inflames in the air, even at a verv low 

 temperature. When it cannot be detached in large pieces, 

 it must be kept in a gas deprived of oxygen, or in naphtha: 

 it was by plunging it in oil that I extracted it from the gun- 

 barrel . 



*' We also find in the gun-barrel portions of amalgamated 

 iron and potassium; they adhere very strongly to the part of 

 the gun-barrel which occupies the middle of the furnace ; 

 they become green in the air, and are easily decomposed : 

 the potash returns in a very short time to its first state. 



" In order to obtain the potassium conveniently, and on a • 

 large scale, we must procure a ^un-barrel of a large diameter, 

 which must be heated throughout a great part of its length, 

 and with a tube at its extremity, in which liquid potash is kept; 

 This tube must be disposed in such a manner that we may 

 be able to let fall whatever quantity. of oxide of liquid potash 

 we please; and we should volatilize it before putting it in 



contact 



