504 NATURE AND OECOMf OSITIOt^ OF THE FfXBD ALKALIS^ 



The base of When the basis of potash is heated with* gold, or silYcr, 



whT!^ow"'lu- "^* copprer, in a close vessel of pore glas^, it rapidly acts upoa 

 •vcr, and cop- them ; aiid when the compounds are thrown into water, this 

 per,aa Hmd is decomposed, potash iormed, and the metals appear 



to be separated unaltered. 

 renders fusibia The basis of potash combines with fusible metal, and 

 tnetai less fusi- f^^,^^^ ^^ ^jj^^^ ^.-.j^ -^^ ^,^-^^^^ j^^^ ^ higher point of fusion 



than the fusible metal. 

 Its action on The action of the basis of potash upon the inflammable 

 oily com- ^jj]„ compound bodies contirms the other facts of the 

 pounds. If- • r 



strength of its attraction for oxigen. 



On naphtha. On naphtha colourless and recently distilled, as I have 

 already 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 g'lobule. 



On concrete On the concrete oils (tallow, spermaceti, wax, for in- 



**^** stance), wfien heated, it acts slowly, coaly matter is de- 



posited, a little gasj* is evolved, and a soap is formed; but 

 in these cases it is necessary that a large quantity of the oil 



On fluid fixed be employed. On the fluid fixed oils it produces the same 



°''5- etfects, but more slowly. 



On volatile By heat likewise it rapidly decomposes the volatile oils; 



^*''^* alkali is'formed, a small quantity of gas is evolved, and 



charcoal is deposited, 



• When a globule of the bi-As of potash is iivtrodiiced into any of the> 

 fixed oils heated, the first product is pure hidiogen, which arises from 

 the decomposition of the water absorbed by the crust of potash during 

 tl'.e exposure to the atmosphere. The gas evolved, when the globule is 

 ireed from this crust, I have found to be carbonated hidrogen requiring 

 more than an equal bulk of oxigen gas for its complete saturation by ex- 

 plosion. I ha'e 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 basis of potash on the oils. Some anomalies occurred 

 which led to the inquiry, and the result was perfectly conclusive, Olive 

 oil, oil of turpentine, and naphtha when decomposed by heat, exhibited 

 as products different proportions of charcoal, heavy inflammable gas, 

 e"mpyreumatic oily matter, and water, so that the existence of oxig^n in 

 them was fully pi-oved ; and accurate indications of the proportions of 

 their elements might be gained by their decomposition by the basis of 

 potash. Naphtha of all furni:jhed least water and carbonic acid, and oil 

 of turpentine the? most. 



When 



