Fill a small tube about half-full with sample and insert a capillary tube, closed end up.
Attach the tube to a thermometer with a small rubber band.
Insert the sample into a Thiele tube, so that the sample is near the middle of the oil.
Heat the arm of the Thiele tube with a burner, gently and continuously.
|Heat until a vigorous stream of bubbles emerges from the capillary tube, such that individual drops can be barely distinguished.
Remove the heat and allow the oil to cool.
The boiling point is the temperature when the oil just begins to enter the capillary tube.