6 
demonstrated by practical experience centuries before it was 
lly understood just in what way the good effects were broug ht 
a ut it is now well established that their fertilizing quali- 
ties are due chiefly to the “potash” or potassium salt 'y 
contain. Potassium, nitrogen, and sphorus are eleme: 
that plants must fi the soil if they are to grow thrive, 
nd of these three essential elements the seaweeds suppl tas- 
3 in Sp bun ce. In addition to supplying potassium, 
the application of seaweeds in bulk appears to have i 
a 
the roots of ae oa a vate plants. bal pore sh a has gone 
into th ers used by ardeners 
of the United nee ae come almost penis from te. mines in 
the Stassfurt region of Gi ar 
sea-bottom where various soluble potas salts have accumu- 
lated in a solid form cae nd final drying out of 
olly dep pon Ge 
ached fertilizers. evi’ to the great war, the United 
¥P~P 
millions of dollars or more annually. Three or four years before 
the war br 
that was allowed to be shipped to the United States, This 
