289 



The Bulletin of Imperial Institute 1911 gives a yield of oil of 

 55.41% of the weight of Kernels oorrespondin,g to 41.76% of the 

 weight of the whole eeeds containdrig: 



kernels . . . . 75.37% 



husks .. .. 24.63% 



Oil Extraction. 

 The extraction of oil consists of three o|X'rations, namely: 

 1st. The grinding of the seed to a fine pulp in order to hreak 

 the oil cells. 



2iid. The lieating of the around seed to facilitate the flow of 

 oil. 



3rd. The pressing of flic judp, to force out the oil, leaving the 

 cake as residue. 



A fourtli operation consists 'in submitting the meal to the 

 action of a chemical solvent in wdiich the oil is dissolved and from 

 which it is separated afterwards, the final residue or oake contain- 

 ing only a. very small percentage of oil. This process which is 

 onl}'. practicable in specially equipped mills does not concern the 

 planter. 



Large modern mills, as already stated, treat the Castor-seed 

 whole, with the husks c«i ; but a hand power plant such as would be 

 called for, to deal with the small crops contemplated in this paper, 

 could not supply the pressure necessary for a.n adequate .expression 

 of the oil from seeds in their husks. 



The sma.ll ])lanter will therefore have either to sell his seeds 

 to the oil-prcssers. or to treat the seeds after, husking them more 

 or less completel\. AVe have shown above how this ]>art of the 

 work can be done. 



The husked seeds have thns to undergo the three ojierations of 

 Grinding, Heating and Pressing. 



Some makers of oil-mill machinery are now supplying hand- 

 mills to meet the requirements of producers who do not use power. 



The Firm of Rose, Downs and Thompson, Ltd. of Hull and 

 Shangbai, supjdy such a mill catalogued as "The Manual Oil-mill 

 No. 359" to crush o(^ ])oun(ls of oil-seeds per hour, and worked by 

 two men. 



"The ]\Ii 11 consists of the following machinerv : one set of 

 Ainglo-American Uolls 3' higli. 6 in. in diameter and fi in. face, 

 hand-driven with heavy fly-wheel; one \vrought iron fire-heated pan 

 or kettle, to be placed on a brick-foundation and worked by hand ; 

 one set of double hydraulic pumps, hand-driven, the large pump 

 being arranged to give the first pressure rapidly, and the small 

 pump to give the final or finishing pressure without a material in- 

 crease of effort from the workman; one hydraulic press, to make 

 five taper cakes 13" x 6" x 5" fitted with corrugated metal plates 

 bearing any desired 'brand ; one 4 in. hydraulic o;auge and pipes; 

 a supply of woollen press Imgs. mending yarn and other needful 

 sundries." 



