34 BULLETIN 867, U. S. DEPARTMENT OF AGRICULTURE. 



Arid number. — (12) It must not require more than 3 milligrams of potassium 

 hydroxid (KOH) or 2.14 milligrams of sodium hydroxid (NaOH) to neutralize i 

 gram of oil. This is equivalent to 1.5 per cent of oleic acid. 



I'nsaponi liable matter. — (13) The unsaponifiable matter must not exceed 1 per 

 cent. Samples used for this test shall weigh 5 to 10 grams. 



Iodin number (Tlanus or Wijs methods). — (14) The iodin number must he between 

 80 and 90. Samples used for this test shall weigh 0.2 to 0.25 gram and shall be treated 

 for 1 hour. 



Rosin ( Licbcrman-Storch test). — (15) The castor oil must not give a reaction for either 

 rosin or rosin oil. 



Cottonseed oil (Halphen test). — (16) The castor oil must not give a reaction for cotton- 

 seed oil. 



Inasmuch as the chemical analysis does not give the final word 

 regarding the adaptability of an oil for lubricating purposes, engine 

 tests have been made on the lubricating value of No. 1 hydraulic- 

 pressed oil, No. 1 expeller oil, and No. 3 refined oil. The results of 

 such tests show these oils to be of equal value for lubricating pur- 

 poses. Since the chemical and physical constants expressed above 

 are practically identical, it follows that color is the only evident 

 means of differentiating between the various oils. A demulsibility 

 test applied to hydraulic-pressed oil compared with expeller oil 

 reacted slightly in favor of the expeller oil. The difference, however, 

 was so slight that the two oils may be considered in this respect 

 practically identical. 



The following statements quoted from leading dealers in castor 

 oil (not manufacturers) show how the trade considers American- 

 produced oil as compared with various imported stocks: 



The American-pressed castor oil will remain free from rancidity for a longer period 

 than the imported oils and as a general average is vastly superior to any imported oil 

 that we have received. 



The oil that comes from China and the Far East seems to be of a decided yellow color 

 and. in the writer's judgment, would indicate that it is hot pressed, i. e., that the oil 

 was pressed from a warm or hot meal. 



In our opinion the oil made in the United States is equal, if not superior, to the im- 

 ported. 



We will say that it has happened that the oil we purchased which was made in this 

 country turned out to be better than that we have used which was made abroad. 



Domestic-manufactured castor oil will keep longer and be freer from acidity than the 

 oil which is imported. Generally speaking, the imported castor oil, especially from 

 the Orient, contains from 1 to 8 per cent acidity and by keeping the oil the acidity 

 is likely to be increased, especially where the oil tests from 3 or 4 to 8 per cent. We 

 look upon the domestic-manufactured white oil as being best not only for medicinal 

 but for manufacturing purposes. 



As a matter of fact, now that the War Trade Board has ruled (January, 1919) that 

 castor beans and castor oil can come freely into this country, we doubt if any of 

 this oil ('oriental) will come here. It is, as you may know, an inferior oil, and can only 

 be used in comparison with a domestic production of No. 3 castor oil. 



