Section III.— THE FORMATION OF OILS 

 IN PLANTS 



Linseed. — lyinseed has already been described under the 

 subject of linen (p. 126), but it is also used for the 

 production of an oil seed. Where the plant is grown in 

 cold, damp climates, the situation favours the production 

 of fibre, but where it is grown in drier and warmer districts 

 the situation favours the production of seed. It can be 

 grown in many countries, but the chief sources of linseed 

 are Russia, India, and the Argentine. lyinseed contains 

 about 35 per cent, of oil, which is expressed both on the large 

 and on the small scale. When linseed is imported into Great 

 Britain it is generally first of all cleaned from its miscellaneous 

 impurities, often amounting to 10 per cent., and the purified 

 linseed run through rollers to crush it without actually 

 expressing oil. It is then passed through a " kettle," where 

 it is subjected either to direct steam heat, or to the heat 

 from steam passing through a coil, or both. Linseed grown 

 in India is very dry, and requires the moisture content 

 to be increased, which is conveniently done by blowing steam 

 into it. lyinseed obtained from the Baltic ports is some- 

 times rather too damp for the process, and the steam is, 

 therefore, passed through a coil, so as to both heat and slightly 

 dry the linseed. The linseed is then placed between felts 

 which are, in turn, placed between corrugated iron sheets, 

 which are built up into a pile of twenty or thirty in a hydraulic 

 press. The name "hydraulic press " is here somewhat of a 

 misnomer, because in practice the liquor used in the pumps 

 is not water, but the oil which is being produced at the time. 

 If water were used, any leak in the press would damage the 

 oil, but when the oil itself is used this is not possible. As 



