1 6 On the Decomposition and Composition 



globule is made to touch a globule of mercury about twice 

 as large, they combine with considerable heat ; the com- 

 pound is fluid at the temperature of its formation ; but when 

 cool it appears as a solid metal, similar in colour to silver. 

 If the quantity of thet>asis of potash is still further increased, 

 so as to be about ^h the weight of the mercury, the amal- 

 gam increases in hardness, and becomes brittle. The solid 

 amalgam, in which the basis is in the smallest proportion, 

 seems to consist of about one part in. weight of basis and 70 

 parts of mercury, and is very soft and malleable. 



When these compounds are exposed to air, they rapidly 

 absorb oxygen ; potash which deliquesces is formed ; and 

 in a few minutes the mercury is found pure and unaltered. 



When a globule of the amalgam is thrown into water, it 

 rapidly decomposes it with a hissing noise ; potash is form- 

 ed, pure hydrogen disengaged, and the mercury remains 

 free. 



The fluid amalgam of mercury and this substance dissolves 

 all the metals 1 have exposed to it j 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 wa- 

 ter, 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 oxygen. . . 



On naphtha colourless and recently distilled, as I have al- 

 ready said, it has very little power of action ; but in naph- 

 tha 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 in- 

 stance,) when heated, it acts slowly, coaly matter is depo- 

 sited, 



