PROCESS FOR METALLIZING POTASH AND SODA. 39 



process, and add to this mixture as much linseed oil as it 

 vvill bear without ceasing to be pulverulent. 



Whatever be the kind of vessel employed to calcine this Manipulation. 

 matter, and whether it be the hrst or second mixture, we 

 must always begin with heating it gradually : but as soon 

 as the matter is obscurely red, the fire may be increased, 

 till a fine sky blue light, surrounded with a greenish aureola, 

 is perceived in the interior of the retort or iron tube. To 

 this light will soon succeed a very copious vapour, which 

 obscures all the interior of the vessel. This is the metal, 

 which is disengaged from the mixture. The fire must then 

 be urged no farther,' for at this temperature the retort be- 

 gins to fuse; and if the iron resist better, it is because the 

 alkali penetrates it less readily than it does the stone ware, 

 and likewise because the heat it receives is sooner transmit- 

 ted to the matter within. 



To collect the metal in proportion as it forms, introduce Collection of 

 into the vacuum of the apparatus a rod of iron well cleaned ; ne me a * 

 and, as it must not have time to grow red hot, take it out 

 again in four or five seconds: it will then be found covered 

 with metal, to remove which the rod is to be plunged in- 

 stantly into a glass cucurbit filled with essence of turpen- 

 tine. This cucurbit should be immersed in a tub of water, 

 to prevent the essence from boiling: and notwithstanding 

 this precaution, it will be heated so much sometimes as to 

 take fire on the immersion of the iron rod. 



To execute these processes well, three persons are neces* Circumstanre* 



sary. One should take care of the fire and work the bel- necessar y to 



mi -iiiii ensure success. 



lows. The most active should collect the metal as it is 



produced, and with the utmost celerity plunge the iron 

 rods into the essence. The third must separate the metal 

 that is on the rods, and then plunge them into water; not 

 only to cool them, but also to remove the alkali, that may 

 have escaped metallization, or been formed by combustion 

 previous to the immersion of the metal in the essence of 

 turpentine. He must likewise take care, to wipe the rods 

 perfectly dry, that he who collects the metal may have no- 

 thing else to do. 



These processes, while the metal is producing, requires 

 in the operators a dexterity not inferior to the celerity I 



have 



