1885.] ^*^* [Carter. 



native olive oil, for the reason that it can be brought to Naples and sold 

 at less than half the cost of producing pure olive oil." The cotton seed 

 oil mixed with pure olive oil is exported to other countries. The price of 

 fine salad oil is from three to four dollars per gallon, while cotton seed 

 oil is worth from seventy to ninety cents per gallon. The oils commonly 

 used to adulterate olive oil are colza oil, sesame oil and peanut oil. In the 

 North of France poppy oil is used frequently because of its cheapness and 

 neutral taste, and in Provence honey is used. In all probability glucose 

 syrup has been tried. Linseed oil, the most important drying oil in the 

 arts, so much used in varnishes and paints, is very often sophisticated. 

 Even the seed from which the oil is made is mixed with other seeds. In 

 India flaxseed is grown with mustard and rape. In Russia various pro- 

 portions of hemp and linseed are sown together. Hemp seed yields an oil 

 of an acrid odor, mild taste and yellow color, used in Russia for burning 

 in lamps and making paints, varnishes and soap. The oils commonly 

 mixed with linseed oil are niger, cotton seed, fish, rosin and coal oils. In 

 this country lard is adulterated with palmnut and cocoanut oil, the latter 

 is a white fat with the peculiar smell of the kernel. It was formerly made 

 by grinding the kernel, boiling with water and subjecting the paste to a 

 great pressure ; a large quantity of milky juice is so obtained which is 

 slowly boiled and the oil separates and is skimmed ofl". Twenty ordinary 

 sized nuts yield about two quarts of oil. The strong taste of these oils is 

 an objection, and may prevent their general use as adulterants and for the 

 manufacture of oleomargarine. Lard oil which is obtained from lard is 

 very valuable as a lubricant for machinery, and is also used for greasing 

 wool in spinning. It is frequently adulterated with fish oils and cotton 

 seed oils. Lard oil is worth one dollar and twenty cents per gallon, 

 while cotton seed oil is worth about one-half as much. 



The chemical analysis and detection of the adulterated oil is sometimes 

 simple, but generally it is a difficult and trying task, especially when three 

 or more oils have been mixed. The determination of the percentage of 

 oil used to adulterate is out of the question and we must often be satis- 

 fied by simply proving that there has been a mixture without knowing the 

 nature of it. But little work has been done on oils compared to the vast 

 amount of research given to other subjects. Chemists have avoided the 

 study and analysis of oils as difficult and uninteresting. We owe almost 

 all we know to the labors of Chevreul and later to the researches of Prof. 

 Allen and others. When oils are examined, chemical tests are the more 

 important, but the physical tests are also very useful. At the present 

 lime we have not a characteristic test for each oil, as we have for each 

 metal, that will distinguish it when mixed with other oils or that will 

 identify it when alone. 



When we examine an oil supposed to be adulterated, much can be 



accomplished by procuring a sample of perfectly pure oil and subjecting 



them both to the same tests and observing their behavior. A sample of 



lard oil supposed to be adulterated was received from a woolen manufac- 



pnoc. AMER. PHiLOS. soc. xxii. 120. 2l. printed may 25, 1885. 



