70 THE ROYAL SOCIETY OF CANADA 



over a period of one hour will show the general agreement of the 

 results for the in^lividual oil and the extent to which the two oils 

 difïer, as indicated by the reading on the weighing arm of the machine. 



Table I 



Readings on Weighing Arm of Friction Machine at Five Minute Intervals 



Saturated Oil Unsaturated Oil 



10.0 6.8 



9.5 . 6.5 



10.0 6.50 



10.0 6.50 



10.05 6.55 



10.03 6.52 



10.05 6.55 



^ 10.05 6.70 



10.00 6.50 

 10.05 6.50 



10.01 6.60 



Load 700 lbs. 



Temperature 33-34°C 



Revolutions per minute 400 



Time 1 hr. 



The averages obtained for a large number of such runs were as 

 follows: 



Average of Readings on Weighing Unsaturated Saturated 



Arm 6.5 lbs. 10.0 lbs. 



Coefficient .009 .014 



Specific viscosity at 35° 3 2.8 



It was thus seen that with this particular oil the unsaturated 

 constituent possesses the greatest lubricating property. However, as 

 the friction varies directly w^ith the viscosity and as the viscosity of 

 the unsaturated portion is greater than the saturated, the real differ- 

 ence is still greater. This difference can be calculated from the usual 



V K _ F 

 formula X = — — — — 



Where X = coefTficient of friction 



F = force to move the hearing 

 P = Load on the hearing 



V = velocity 



K = coefficient of viscosity 



Y = thickness of the oil film. 



