13 



with a gum, gum resins, and if mixed with benzoic or einnamic acid, 

 balsams. 



Experiments: Use commercial rosin. (Resin). 

 1. Test solubility in alcohol, water, turpentine, and boiling 



sodium hydrate solution. Explain your results. 



Volatile and Fixed Oils 



Oils exist as fixed and volatile, or essential. An oil is a sub- 

 stance that greases, which leaves a stain when dropped on cloth that 

 water will not was'h off, a stain which renders paper translucent. 

 They are termed fixed or volatile according to the permanency of 

 this stain on warming, characters clearly defined by the name given 

 to the two groups. Volatile oils are odorous principles, physically 

 resembling the fixed oils but differing from them in being volatile 

 and by being soluble in alcohol. To this group is due the odor of 

 plants. They are called essential oils from the fact that they pos- 

 sess in a concentrated state the properties of the plants from which 

 they are obtained. 



Experiments : Use oil of turpentine for volatile and cot- 

 ton seed oil for fixed oil. 



1. Prepare 2 series of test tubes of 5 each. To series A, add 



1 mil of oil of turpentine and to series B, 1 mil of cotton 

 seed oil. 



To No. 1 of each series add 5 mils of water. 

 To No. 2, 5 mils of alcohol. No. 3, 5 mils of chloroform. 

 No. 4, 5 mils of ether, and to No. 4, series A, 5 mils of 

 cotton seed oil and to No. 5, series B, 5 mils of oil of tur- 

 pentine. Shake all and note solubility. Tabulate results. 



2. Put a drop of oil of turpenbine on glazed paper. Results. 



Heat high over a flame for a few minutes. Results. 

 Repeat the experiment using cotton seed oil instead of 

 oil of turpentine. 



3. Rotate a glass stopper in the neck of a bottle of fixed oil, 



water, volatile oil. Note any differences. Which one 

 greases the stopper ? These bottles will be supplied. 



