Extraction of Oil 529 



Further particulars given by Mr. Walker in 

 connection with these eleven series include : 



Q IO II 



I9'I 2O*I 19-5 



42-5 42-1 39'& 



13-8 147 I2'0 



38-4 37-8 407 



21*6 22*0 197 



272 354 370 



65^0 61-9 



* 35-o 38-1 

 * Copra destroyed by accident. 



Extraction is sometimes undertaken for the 

 production of oil only, sometimes for the manu- 

 facture of oil and a feeding cake, and occasion- 

 ally for the production of oil and a fertilizing 

 material. 



If a cattle cake is required then the oil is 

 perhaps more safely obtained by expression, but 

 if the residue is only required as a fertilizer, or, 

 as sometimes happens, owing to the absence of 

 a market or any local demand for the cake, is 

 entirely a waste product, then more satisfactory 

 results are obtained by extraction by means of 

 a solvent. 



The difference between the results of the 

 two methods lies in the yield of oil obtained. 

 The expression process obtains only a proper-. / 

 tion of the oil, the balance remaining behind in 

 the cake to the benefit of the cattle, and in most 

 countries the laws governing the sale of such 

 cattle food demand a certain minimum percen- 

 tage of oil. 



34 



