IODINE AND OTHER CHEMICALS 65 



efforts resulted in a process resembling the by-prod- 

 uct coking of coal, by which iodine, bromine, po- 

 tassium salts, an illuminating gas, light and heavy 

 oils, ammonia, acetic acid, and charcoal were ob- 

 tained. The dried seaweed is destructively distilled, 

 that is, heated in air-tight retorts, and the distillate 

 is caught in special condensers. The residue consists 

 of charcoal, potassium salts, and iodides. These salts 

 are leached out of the charcoal and separated by 

 fractional crystallization according to a process 

 similar to the one used in the treatment of seaweed 

 ashes. 



Stanford also discovered a method of obtaining 

 alginic acid, iodine, and potassium salts from 

 seaweed. 



Potash and Other Products from the 

 Giant Kelp 



The outbreak of the World War cut off America's 

 supply of potassium salts, which had formerly been 

 obtained from the Stassfurt mines in Germany. Since 

 potassium salts are essential for agriculture and 

 many industries, it became necessary to develop the 

 American potash resources. The high potassium con- 

 tent of a giant Pacific coast seaweed, called kelp, 

 was one of the first sources of potash to attract at- 

 tention. Because of the acute shortage of all po- 

 tassium salts, the Department of Agriculture made 

 a general survey of the various kelp beds along the 

 coast and established an experimental factory to 

 demonstrate methods of producing potash and other 

 products from the kelp. The survey located approxl- 



