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The World's Commercial Products 



Photo by W. H. John 



only country from which both flax 

 and linseed are produced on a 

 commercial scale. In Europe the 

 flax plant is grown chiefly for 

 fibre. In other countries, notably 

 in the United States, Argentine, 

 Uruguay, and British India, which 

 with Russia produce the bulk of the 

 world's supply of linseed, the plant 

 is grown almost exclusively for seed. 

 The most interesting difference 

 in variety exists between white- 

 seeded and red-seeded forms, as 

 recognised in India, although the 

 statement is made that plants 

 raised from white seed in certain 

 soils produce — by reversion — red 

 seed. The quality of oil from the 

 white seed is generally reckoned 

 superior. 



It is found advantageous to 

 keep the seed for a few months 

 before it is pressed for oil. Sifting, 

 screening and grinding between 

 rapidly- revolving rollers are neces- 

 sary operations preliminary to 

 pressing. Hot -pressing is usually 

 practised, although the best grades 

 of linseed oil, serving occasionally, as in Russia, for edible purposes or for mixing with 

 paint, are cold pressed. The mucilage contained in the seed-coats known as " foots " has 

 to be separated from the expressed oil, this being effected by forcing the oil through filter 

 presses. There is no objection to the extraction of oil from the seed, and in America naphtha 

 has been used for the purpose. The linseed oil is run into percolators, holding about 1,000 

 bushels of seed, where it is flooded with naphtha ; separation of the linseed oil and naphtha is 

 produced in the ordinary way by distillation. 



The colour of linseed oil varies from a light to a brownish-yellow. The oil possesses an 

 acrid taste and smell, soon becomes rancid on exposure to the air, and has the property 

 of taking up oxygen from the air and drying to an elastic skin. This drying property is con- 

 siderably increased by heating the oil with certain metallic salts, e.g., litharge, known as 

 " driers," producing the so-called " boiled " linseed oil, although it is now known that a 

 temperature of 65° C. is sufficient for the purpose. The principal uses of boiled linseed oil are 

 for making paints and varnishes, in the preparation of printers' ink, and in the manufacture 

 of linoleum. 



The following drying oils are also commercial : — - 



Candle-nut Oil derives its name from the custom of the natives in the South Sea Islands, 

 who fix the seeds on bamboo and burn them as candles. The tree (Aleurites moluccana) is 

 widely diffused throughout the Polynesian Islands and thence northwards to the Malay 

 Peninsula. The oil dries about as rapidly as linseed and is suitable for varnishes, also for 

 making soft soap. 



Tung or Wood Oil is a Chinese product obtained chiefly from the seeds of Aleurites cor data, 

 a good-sized tree growing wild, and also planted along the roadsides in China and Japan. 



GOLD COAST. MILLER S PALM NUT-CRACKING 

 MACHINE AT WORK 



