Let us now turn to the most valuable of the cottonseed products, the oil.  The seed contains about twenty per cent. of oil, most of which can be squeezed out of the hot seeds by hydraulic pressure.  It comes out as a red liquid of a disagreeable odor.  This is decolorized, deodorized and otherwise purified in various ways:  by treatment with alkalies or acids, by blowing air and steam through it, by shaking up with fuller’s earth, by settling and filtering.  The refined product is a yellow oil, suitable for table use.  Formerly, on account of the popular prejudice against any novel food products, it used to masquerade as olive oil.  Now, however, it boldly competes with its ancient rival in the lands of the olive tree and America ships some 700,000 barrels of cottonseed oil a year to the Mediterranean.  The Turkish Government tried to check the spread of cottonseed oil by calling it an adulterant and prohibiting its mixture with olive oil.  The result was that the sale of Turkish olive oil fell off because people found its flavor too strong when undiluted.  Italy imports cottonseed oil and exports her olive oil.  Denmark imports cottonseed meal and margarine and exports her butter.

Northern nations are accustomed to hard fats and do not take to oils for cooking or table use as do the southerners.  Butter and lard are preferred to olive oil and ghee.  But this does not rule out cottonseed.  It can be combined with the hard fats of animal or vegetable origin in margarine or it may itself be hardened by hydrogen.

To understand this interesting reaction which is profoundly affecting international relations it will be necessary to dip into the chemistry of the subject.  Here are the symbols of the chief ingredients of the fats and oils.  Please look at them.

Linoleic acid       C_{18}H_{32}O_{2}
Oleic acid          C_{18}H_{34}O_{2}
Stearic acid        C_{18}H_{36}O_{2}

Don’t skip these because you have not studied chemistry.  That’s why I am giving them to you.  If you had studied chemistry you would know them without my telling.  Just examine them and you will discover the secret.  You will see that all three are composed of the same elements, carbon, hydrogen, and oxygen.  Notice next the number of atoms in each element as indicated by the little low figures on the right of each letter.  You observe that all three contain the same number of atoms of carbon and oxygen but differ in the amount of hydrogen.  This trifling difference in composition makes a great difference in behavior.  The less the hydrogen the lower the melting point.  Or to say the same thing in other words, fatty substances low in hydrogen are apt to be liquids and those with a full complement of hydrogen atoms are apt to be solids at the ordinary temperature of the air.  It is common to call the former “oils” and the latter “fats,” but that implies too great a dissimilarity, for the distinction depends on whether we are living in the tropics or the arctic.  It is better, therefore, to lump them all together and call them “soft fats” and “hard fats,” respectively.