10 



BULLETIN 439, U. S. DEPARTMENT OF AGRICULTURE, 



the soy bean are similar to those employed with other oil seeds, such 

 as cottonseed and linseed. 



In Manchuria the manufacture of oil and oil cake is not confined 

 to large centers, as every small center of bean production has its 

 native mill. The method of extracting oil in these native mills is 

 decidedly primitive. The beans are first crushed beneath a mill- 

 stone and then steamed for about 15 minutes. The resultant mass 

 is spread out and placed in circular iron frames, about 6 inches deep. 

 Five of these frames are placed one above another in a vertical press, 

 consisting of four uprights, with crossbeams at the top and bottom. 

 Pressure is apphed by means of wedges driven in between the cross- 



FiG. 3.- Coolies at Newchwang, Manchuria, engaged in carrying loads of soy beans from the junks to big 

 stacks, where they are kept until the factory needs them for oil manufacture. (Photographed by F. N. 

 Meyer.) 



beams and beams placed on top of the frames, and the oil is thus 

 expressed. During the last few years large bean mills equipped with 

 modern machinery have been erected, and these are able to extract 

 3 or 4 per cent more oil (fig. 3). In these large bean mills only about 

 one-half the oil is extracted by the usual process; that is, by crushing 

 the beans, steamhig them, and using hydrauhc pressure. 



A solvent process of extraction, involving the use of benzine, has 

 recently come into use in several Enghsh miUs, and three such miUs 

 are in operation in Manchuria and Japan. The seeds are first finely 

 crushed and then treated directly by the fat solvent. The oil is 

 then taken out of the fat solvent by evaporating the latter, which 

 is distilled and used over again. The residue is weU dried and then 

 ground into a fine meal, which is said to contain no detectable trace 



