The determination consists in slow and progressive cooling of the essential oil and observation of the variations in temperature as the oil passes from the liquid to the solid state. The apparatur for determination of freezing point consists of a wide-mouthed container of about 500 ml capacity, provided with a bored cork or rubber stopper into which a stout-walled test tube is inserted. Another smaller test tube is fitted into the stout-walled test tube by means of another bored cork or rubber stopper. Into the smaller test tube a thermometer is inserted.