of t he fixed Alkalis. 1 7 



sited, a little gas * is evolved, and a soap is formed ; but in 

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

 employed. On the fluid fixed oils it produces the same 

 effects, but, more slowly. 



By heat likewise it rapidly decomposes the volatile oils; 

 alkali is formed, a small quantity of gas is evolved, and 

 charcoal is deposited. 



When the basis of potash is thrown into camphor in fu- 

 sion, the camphor soon becomes blackened, no gas is libe- 

 rated in the process of decomposition, and a saponaceous 

 compound is formed ; which seems to show that camphor 

 contains more oxygen than the volatile oils. 



The basis of potash readily reduces metallic oxides when 

 heated in contact with them. When a small quantity of 

 the oxide of iron was heated with-it, to a temperature ap- 

 proaching its point of distillation, there was a vivid action;' 

 alkali and gray metallic particles, which dissolved with ef- 

 fervescence in muriatic acid, appeared. The oxides of lead 

 and the oxides of tin were revived still more rapidly ; and 

 when the basis of potash was in excess, an alloy was formed 

 with the revived metal. 



In consequence of this property, the basis of potash rea- 

 dily decomposes flint glass and green glass, by a gentle heat;" 

 alkali is immediately formed by oxygen from the oxides, 

 which dissolves the glass, and a new surface is soon exposed 

 to the agent. 



* When a g-lobule of the basis of potash is introduced into any of the fixed 

 oils heated, the first product is pure hydrogen, which arises from the de- 

 composition of the water absorbed by the crust of potash during the expo- 

 sure to the atmosphere. The gas evolved, when the globule is freed from 

 this crust, I have found to be carbonated hydrogen, requiring more than an 

 equal bulk of oxygen gas for its complete saturation by explosior, I have 

 made a great number of experiments, which it would be foreign to the ob- 

 ject 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 naph- 

 tha, when decomposed by heat, exhibited as products different proportions 

 of charcoal, heavy inflammable gas, empyreumatic c'y matter, ^and water, 

 so that the existence of oxygen in them was fully proved; and accurate in- 

 dications of the proportions of their elements might be gained by their de- 

 composition by the basis of potash. Naphtha of all furnished least water and 

 tarbonic acid, and oil of turpentine the most'. 



Vol. 32. No. 125, Oct, 1808. B At 



