NUT OILS. 109 



there is no practicable method of extraction which would yield a 

 mixture of pure fats. Petroleum ether undoubtedly yields an 

 extract freer from impurities than ethyl ether, but its higher 

 boiling point would render it more difficult to remove. 



Some of these nut oils are very complex compounds. Cocoa- 

 nut oil contains large proportions of trimyristin and trilaurin, 

 smaller quantities of tripalmitin and triolein, and also the glyce- 

 rides of the volatile caproic, caprylic and capric acids.* The 

 walnut contains myristic and lauric acids, together with oleic, 

 linolic, linolenic and isolinolenic acids.f Among the bodies not 

 fats which frequently occurs are the lecithins, cholesterin and 

 chlorophyl. 



Of the oils here reported, those from the cocoanut and 

 pistachio present the most marked peculiarities. Above 24 C. 

 the former is perfectly colorless and clear as water. At the 

 ordinary room temperature it hardens to an opaque white solid. 

 The pistachio oil is a dark yellowish green, perhaps through the 

 presence of chlorophyl. All the other oils are fluids at ordinary 

 temperatures and to the casual observer present few points of 

 difference, except as regards color, which varies from light straw 

 to deep amber. For the most part they are without pronounced 

 odor, though several readily suggest the nuts from which they 

 were derived. 



The instrument used in determining the refractive index was 

 that of the Societe Genevoise, furnished for the purpose by 

 Prof. Stevens of the department of physics of the University. 

 The instrument permits very accurate measurements. Although 

 from four to six readings were taken for each oil, the variations 

 were for the most part confined to the fifth decimal, here omitted. 

 The temperature selected was that of the room at the time the 

 work was begun. The specific gravity was determined by a 

 carefully calibrated pyknometer, the standard chosen being dis- 

 tilled water at the same temperature, 24 C. The combustions 

 were made in a bomb calorimeter of the Atwater model, made 

 by O. S. Blakeslee of Middletown, Conn. Even with the usual 

 pressure of oxygen, twenty atmospheres, it was found impos- 

 sible to ignite the oil directly. After several unsuccessful 



*Lewkowitscli, Oils, Fats and Waxes, p. 53S. 

 t Ibid, p. 350. 



