i8 Mr. Davy's Lecture on the Decomposition and Composition 
rapidly decomposes it with a hissing noise ; potash is formed, 
pure hydrogene disengaged, and the mercury remains free. 
The fluid amalgam of mercury and this substance dissolves 
all the metals I have exposed to it ; and in this state of union, 
mercury acts on iron and platina. 
When the basis of potash is heated with gold, or silver, or 
copper, in a close vessel of pure glass, it rapidly acts upon 
them ; and when the compounds are thrown into water, this 
fluid is decomposed, potash formed, and the metals appear to 
be separated unaltered. 
The basis of potash combines with fusible metal, and forms 
an alloy with it, which has a higher point of fusion than the 
fusible metal. 
The action of the basis of potash upon the inflammable oily 
compound bodies, confirms the other facts of the strength of 
its attraction for oxygene. 
On naphtha colourless and recently distilled, as I have al- 
ready said, it has very little power of action ; but in naphtha 
that has been exposed to the air it soon oxidates, and alkali is 
formed, which unites with the naphtha into a brown soap that 
collects round the globule. 
On the concrete oils (tallow, spermaceti, wax, for instance), 
when heated, it acts slowly, coaly matter is deposited, a little 
gas* is evolved, and a soap is formed ; but in these cases it is 
* When a globule of the basis of potash is introduced into any of the fixed oils 
heated, the first product is pure hydrogene which arises from the decomposition of the 
water absorbed by the crust of potash during the exposure to the atmosphere. The 
gas evolved, when the globule is freed from this crust, I have found to be carbo- 
nated hydrogene requiring more than an equal bulk of oxygene gas for its complete 
saturation by explosion. I have made a great number of experiments, which it would 
be foreign to the object of this lecture to give in minute detail, on the agencies of the 
