14 Mr. Davy’s Lecture on the Decomposition and Composition 
instantly burns with a bright flame, and a deep hole is made 
in the ice, which is found to contain a solution of potash. 
The theory of the action of the basis of potash upon water, 
exposed to the atmosphere, though complicated changes occur, 
is far from being obscure. The phenomena seem to depend 
on the strong attractions of the basis for oxygene and of the 
potash formed for water. The heat, which arises from two 
causes, decomposition and combination, is sufficiently intense 
to produce the inflammation. Water is a bad conductor of heat ; 
the globule swims exposed to air ; a part of it, there is the 
greatest reason to believe, is dissolved by the heated nascent 
hydrogene ; and this substance being capable of spontaneous 
inflammation, explodes, and communicates the effect of com- 
bustion to any of the basis that may be yet uncombined. 
When a globule confined out of the contact of air is acted 
upon by water, the theory of decomposition is very simple, 
the heat produced is rapidly carried off, so that there is no 
ignition ; and a high temperature being requisite for the solu- 
tion of the basis in hydrogene this combination probably does 
not take place, or at least it can have a momentary existence 
only. 
The production of alkali in the decomposition of water by 
the basis of potash is demonstrated in a very simple and 
satisfactory manner by dropping a globule of it upon mois- 
tened paper tinged with turmeric. At the moment that the 
globule comes into contact with the water, it burns, and moves 
rapidly upon the paper, as if in search of moisture, leaving 
behind it a deep reddish brown trace, and acting upon the paper 
precisely as dry caustic potash. 
So strong is the attraction of the basis of potash for oxygene. 
