Improvements on Brunner^s process for Potassium. 315 



um being then introduced, and the open end of the tube, closed by 

 means of a spirit lamp, the metal may be fused, and with a little 

 dexterity may be transferred in pure globules to that part of the cav- 

 ity of the tube which is between the sealed end and the narrow part. 

 This object being effected, the tube is divided at that part, and seal- 

 ed by fusion. 



In this case the potassium usually falls upon the glass and adheres 

 to it, presenting a perfectly brilliant metallic coating, and preserves 

 this appearance without diminution for years. 



It is however liable to inflammation from slight causes when kept 

 without naphtha. I had an ounce of it in a small phial for eighteen 

 months which took fire on my venturing to divide the phial by means 

 of a file. 



An account of an explosive compoimd produced by the reaction of 

 naphtha with potassium, by the author of the preceding article. 



I avail myself of this opportunity of mentioning a circumstance 

 which occurred in January, 1831, and which I should have mention- 

 ed before, had I not hoped to have had leisure to ascertain the cause 

 of the phenomenon. 



Having some globules of potassium of a size so small, as to be 

 separated with difficulty from the naphtha with which they had been 

 intermingled. I endeavored to get rid of the naphtha by heat. With 

 this view I heated the whole mass in a sealed tube, properly recurv- 

 ed to act as a retort. The glass, when heated to the boiling point of 

 the naphtha, became quite black so as to lose its transparency. When 

 all the naphtha had been expelled, I inverted the tube in another of a 

 larger size filled with hydrogen, and otherwise prepared as above 

 mentioned. A few globules of the metal ran into the tube thus pre- 

 pared, and were secured there ; so that to this day their brilliancy is 

 unimpaired, and they still have in some points, a striking degree of 

 brightness. They are accompanied by a few drops of colorless naph- 

 tha, which is still unchanged. 



Being dissatisfied with the quantity of potassium thus procured, I 

 proceeded to examine the caput mortuum left in the tube used as a 

 retort. With this view striking it with a hammer, I was startled by 

 a violent detonation. From the circumstance that this result was the 

 consequence of the reaction of potassium, naphtha, and flint-glass, 

 it seems to be distinguished from the explosions which are well 

 known to occur in the process above alluded to, by which potassium 

 is obtained from carbonate of potash, according to Brunner. 



