Assessment of oil quality by two accelerated oxidation tests gave little or no correlation with organoleptic asessment during storage. Improvements in quality of oils refined in the factory, to which antioxidants had been added, are indicated by the accelerated tests but are not reproduced in normal storage. Howver a treatment of the oils with alumina, as a part of the refining process replacing earth bleaching, appears to remove antagonistic factors, and under these circumstances the addition of antioxidant has a pronounced effect.

The effect of film losses by evaporation on the spreading characteristics of hexadecanol crystals is examined. It is shown that steady‐state pressures lower than the equilibrium spreading pressure are exhibited and that these are dependent on the ratio of crystal perimeter to film area. The results have been used to evaluate the spreading constant over a range of pressures.

The spontaneous formation of monolayers from single hexadecanol crystals has been examined. It is confirmed that the rate of generation of a monolayer is, at constant temperature, proportional to the extent of the air/water/crystal triple interface. Surface solution occurs directly from the properly formed crystal lattice and not necessarily from active centres only. The effect of film dissolution into the substrate on the spreading process is examined.

No abstract