Experiments for obtaining and preserving Potassium. 2 1 1 



it. From a quarter before, until a quarter past twelve, the beautiful 

 green vapors of potassium, resembling the dense flame of alcohol, 

 tinged by copper, constantly filled the tube. From this time till one, 

 the operation continued, but with less energy, and the vapor of the 

 metal was less distinctly seen. At one, the tube was choked, as was 

 indicated by the cessation of gas from the safety tube. The cork 

 was instantly removed, and an iron rod one quarter of an inch in di- 

 ameter forced through the tube into the retort ; the gas again made its 

 appearance, the cork was replaced and all went on as before till a 

 quarter past one, when the tube was again full, and as the rod could 

 not be easily forced through, the grate was dropped by pulling away 

 its support with the hook/ as seen in fig. 2. A clean cork accurately 

 fitting the tube was applied and the whole left to cool ; when this was 

 accomplished, the alloy was removed and immediately distilled, 

 yielding one ounce and ten grains of the metal. 



Purification of the Potassium. 



The alloy is to be put into an iron retort of a capacity just suffi- 

 cient to contain it, having its tube a little inclined from a horizontal 

 position, so that the metal as fast as reduced will run down and drop 

 into the receptacle. The apparatus which I have used for the want 

 of a better, and whose only defect is its small size, consists of a gun- 

 barrel enlarged at the breech into a cup containing about a half pint. 

 This is inserted in the furnace in the above mentioned position, with 

 the tube projecting and kept at a temperature sufficient to preserve 

 the metal in a fluid state, which may be done by supporting a wire 

 cage of lighted charcoal beneath. The fire having been lighted in 

 the furnace, and the retort heated to redness, the temperature should 

 be kept up as long as any of the metal comes over. 



Method of collecting and preserving the Potassium. 



The French potassium, which has been thus far, almost the only 

 kind sold in our shops, is put up in small globular masses weighing 

 from a few grains to a half a drachm. This method causes a large 

 surface of the metal to be exposed to the action of oxidizing agents, 

 prevents its metallic lustre from being satisfactorily exhibited without 

 removing it from the bottle into the air, and causes much of this valu- 

 able article to be wasted. 



