88 THE WEALTH OF THE SEA 



The freezing operation is the trick in the manufac- 

 ture which not only effects a remarkable change in 

 the structure of the agar but purifies it. The freez- 

 ing causes the water to crystallize out, so that when 

 the jelly thaws, most of the water runs out, taking 

 with it the substances which are soluble in cold water. 

 After thawing, the agar is left to dry in the sun. 

 The dried agar is tied into bundles and marketed 

 in this form. In some of the more modern factories, 

 artificial refrigeration is employed for the freezing 

 of the agar jelly. This permits the factories to 

 operate the whole year, as the manufacturers do not 

 have to wait for cold weather to freeze the kanten. 



The agar industry is one of the American indus- 

 tries which have been introduced since the World 

 War. In 1920, a factory having a capacity of 

 approximately a ton a day was built at Tropico, 

 California. In that vicinity are large quantities of 

 red algae suitable for the manufacture of this valu- 

 able seaweed jelly. The factory is of modern design 

 and manufactures agar of high quality. Here the 

 seaweed is bleached by spreading it out in the sun 

 and washing it with a whirling spray of water. The 

 plant is equipped with a modern refrigerating sys- 

 tem, so that it is independent of weather conditions. 

 Agar is so expensive that, even though the daily 

 production is small, the value is great. 



Chemically agar consists chiefly of a carbohydrate, 

 a galactan called gelose, resembling in many of its 

 properties the pectins, which are the jelly-forming 

 components of fruits. Agar must be pure to be of 



