274 HISTORICAL INTRODUCTION TO CHEMISTRY CHAP. 



As the result of little more than a month's work, Davy 

 found himself in a position to "demonstrate the decom- 

 position and composition" of the caustic alkalies. 



On applying the current to saturated solutions of potash 

 and soda, Davy found that " the water of the solutions alone 

 was affected, and hydrogen and oxygen disengaged with 

 the production of much heat and violent effervescence " 

 (A.C.R. VI. 7). 



" The presence of water appearing thus to prevent any 

 decomposition," Davy passed the current through " potash 

 in igneous fusion," and found that " a most intense light was 

 exhibited at the negative wire, and a column of flame, which 

 seemed to be owing to the development of combustible 

 matter, arose from the point of contact." 



All attempts to isolate the combustible matter under these 

 conditions failed, because the heat required to melt the 

 potash was more than sufficient to ignite the inflammable 

 product. Bu-t when Davy employed "electricity as the 

 common agent for fusion and decomposition," metallic 

 globules appeared at the negatively-charged surface ; whilst 

 oxygen was produced at the positive pole. 



"A small piece of pure potash, which had been exposed 

 for a few seconds to the atmosphere, so as to give conduct- 

 ing power to the surface, was placed upon an insulated disc 

 of platina, connected with the negative side of the battery 

 . . . and a platina wire, communicating with the positive 

 side, was brought in contact with the upper surface of the 

 alkali. The whole apparatus was in the open atmosphere." 



" Under these circumstances a vivid action was soon 

 observed to take place. The potash began to fuse at both 

 its points of electrization There was a violent effervescence 

 at the upper surface ; at the lower, or negative surface, there 

 was no liberation of elastic fluid ; but small globules having 

 a high metallic lustre, and being precisely similar in visible 

 characters to quicksilver, appeared, some of which burnt 

 with explosion and bright flame, as soon as they were formed, 



