REPORT OF THE SECRETARY OF AGRICULTURE. 25 



domestic sources of potash : The giant kelp of the Pacific coast from 

 Lower California to Alaska; the alunite deposits, mainly in the 

 mountains of Utah ; the f eldspathic rocks of the eastern part of the 

 United States ; and the mud of Searles Lake, in California. 



Undoubtedly a large supply of potash salts could be obtained from 

 the giant kelp. The kelp beds have been surveyed and a report, 

 accompanied by maps showing in detail their extent and location, 

 has been issued. Harvesting is accomplished easily, as the kelp grows 

 in open water and barges fitted with mowing attachments can be used. 



For utilizing the kelp several methods are feasible. It may be 

 dried and ground. In this condition it contains all the salts originally 

 present, which are mainly potassium chlorid and sodium chlorid. 

 This material has ideal mechanical properties for use in mixed 

 fertilizers. When the pure potassium chlorid is desired it is nec- 

 essary to separate the juice from the organic material and then 

 to remove the sodium chlorid. The latter can be done readily by 

 recrystallization ; but the separation of the juice from the organic 

 material is more difficult, for the reason that the kelp is nonfibrous 

 and in attempts to effect separation by filtration the filters become 

 clogged and unworkable. The problems yet to be worked out com- 

 mercially are the best methods of drying the wet kelp and of effect- 

 ing the ready and efficient separation of the plant juices from the 

 organic material. Investigation of these questions has proceeded far 

 enough to indicate that their solution should not be very difficult. 



But the development of a supply of potash from the kelp beds is 

 still remote. There are several reasons for this. No one knows how 

 long the European war may last or how soon potash from the 

 former usual sources may be available. The American fertilizer 

 companies heretofore have depended largely on the mining of phos- 

 phate rock and the manufacture of sulphuric acid for superphos- 

 phates. In these lines they are deeply interested financially. There 

 is, furthermore, an element of doubt as to the control of the kelp beds. 

 Just what jurisdiction the Federal Government has over them does 

 not appear, and the Pacific Coast States have not legislated concern- 

 ing those lying opposite their shores. It is unlikely, even in the event 

 of an early peace, that there immediately will be a great supply of 

 potash salts. It is a question how long it would take the former 

 agencies to resume their usual operations. The experts of the depart- 

 ment are of the opinion that under normal conditions, if the Panama 



