SIR HUMPHREY DAVY 189 



the decomposition of potash and soda into oxygen and two peculiar 

 substances, as there is for the decomposition of sulphuric and phos- 

 phoric acids and the metallic oxides into oxygen and their respective 

 combustible bases. 



In the analytical experiments, no substances capable of decomposi- 

 tion are present but the alkalies and a minute portion of moisture ; 

 which seems in no other way essential to the result, than in rendering 

 them conductors at the surface : for the new substances are not gen- 

 erated till the interior, which is dry, begins to be fused ; they explode 

 when in rising through the fused alkali they come in contact with the 

 heated moistened surface ; they cannot be produced from crystallised 

 alkalies, which contain much water ; and the effect produced by the 

 electrization of ignited potash, which contains no sensible quantity of 

 water, confirms the opinion of their formation independently of the 

 presence of this substance. 



The combustible bases of the fixed alkalies seem to be repelled as 

 other combustible substances, by positively electrified surfaces, and 

 attracted by negatively electrified surfaces, and the oxygen follows the 

 contrary order ; or the oxygen being naturally possessed of the nega- 

 tive energy, and the bases of the positive, do not remain in combina- 

 tion when either of them is brought into an electrical state opposite to 

 its natural one. In the synthesis, on the contrary, the natural energies 

 or attractions come in equilibrium with each other; and when these 

 are in a low state at common temperatures, a slow combination is 

 effected ; but when they are exalted by heat, a rapid motion is the re- 

 sult ; and as in other like cases with the production of fire. 





luj; LIBRARY!^ 



