This section is from the book "A Practical Treatise On Friction, Lubrication, Fats And Oils", by Emil F. Dieterichs. Also available from Amazon: A practical treatise on friction, lubrication, fats and oils.
When the market price of lard oil is high and that of cottonseed oil is low, the former is often adulterated with the latter. It is also adulterated with petroleum oils, especially prepared for that purpose, and with addition of refined and deodorized rosin oil, to equalize the specific gravity of the mixture to that of pure lard oil. No. 1 lard oil is adulterated with white neutral oil and No. 2 lard oil is adulterated with yellow neutral oil.
Olive oil is also much adulterated with cottonseed oil, sunflower oil and others, when their market prices, being lower than that of olive oil, warrant such adulteration.
Sperm oil is much adulterated with cheaper fish oils, well refined, deodorized and bleached.
Linseed oil is adulterated with corn oil, cottonseed oil, rapeseed oil, hempseed oil and rosin oil.
Sperm oil should not contain less than four per cent of cetin unless adulterated. Shake one part by weight of sulphuric acid of 1.84 specific gravity, with four parts of the oil; allow to stand for about twenty minutes, shaking twice; add three ounces of distilled water, shake well and allow to stand sixteen to twenty hours; dilute then with three or four times its volume of distilled water and mix thoroughly. On standing the cetin floats on top and can readily be skimmed off; then wash, dry and weigh. It is soluble in chloroform. Castor oil is adulterated with blown oils, such as linseed, rape or cottonseed and rosin oils. If only ten per cent of them be present, they cause a turbidity with absolute alcohol, with which castor oil is miscible in every proportion.