304 Kenneth A. MlcJde: 



These solutions in some cases still showed opacity after stand- 

 ing for a week. 



When 10 c.c. of the substance was added to 60 c.c. of water 

 and agitated witli air, after standing for some time, a layer 

 of white emulsion was noticed between the layer of oil and the 

 surface of the water. This was greatest in the case of machine 

 oil and oleic acid. 



The following list gives the order in which the various sub- 

 stances come with regard to the amount of emulsion formed : — - 



1. Machine oil and oleic acid. 



2. Oil of winter-green. 



3. Naphtha. 



4. Kerosene. 



5. Eucalyptol. 



6. Turpentine. 



The other substances showed no enmlsion. 



In the case of oil of winter-green, the emulsion occurred on 

 the top of the oil, which, being heavier than water, sank to the 

 bottom of the measuring cylinder. 



In conducting these tests Avith oils and water, it was noticed 

 that some oils at once spread out to form a film over the surface 

 of the water, while others remain in the form of a globule. 



Some of the light thin oils when added as a drop to a large 

 surface of water will spread out in a very thin film to such an 

 extent that the iridescence disappears in the centre of the area. 



The following oils spread out as a thin film on the surface of 

 water when the oil was added as a drop to the water : — turpen- 

 tine, phellandrene, gasolene, naphtha, eucalyptol, kerosene. 

 Oleic acid formed a film with one drop, but on adding another 

 drop, the second remained as a globule. 



The following oils remained as globules on the surface of the 

 water : — cotton seed oil, machine oil, engine oil. 



This property of oil depends apparently to a large extent on 

 the viscosity of the oil, for as a rule, and with the thin oils, a film 

 was formed, and with the thicker oils the drop remained as a 

 globule. Viscosity is not, however, the only determining factor, 

 as some of the more viscous oils were found to form films, and 

 some interaction between the surfaces of the oil and water must 

 take place. 



