INTRODUCTION 8 
ECONOMIC POSSIBILITIES 
The possible economic importance of the marine algae has 
been emphasized of late by the investigations that have been 
carried on by the U. S. Department of Agriculture as to their use 
as a source of “potash” for agricultural fertilizers. Тһе kelps 
of the Pacific coast of the United States in particular are the sub- 
ject of several taxonomic, biologic, and chemical papers published 
in a recent report on ‘Fertilizer Resources of the United States.’’* 
In the letter of transmittal accompanying this report, Hon. James 
Wilson, Secretary of Agriculture, remarks: 
“But in the giant kelps of the Pacific coast there is a potential 
source of potash salts which can certainly yield annually some 
three or four times the amount now used in this country, and under 
the best management might even rival the famous Stassfurt 
deposits. It is regarded as a very conservative estimate to put 
the annual yield of potassium chloride from the Pacific kelps at 
upward of 1,000,000 tons, worth at present prices nearly $40,000,- 
000.” 
То a similar statement, Milton Whitney, Chief of the Bureau 
of Soils, adds: “ Moreover, it should be perfectly feasible to cover 
most, if not the entire, cost of production of this vast ‘crop’ by 
the iodine and other by-products produced simultaneously.” 
Dr. J. W. Turrentine (loc. cit. 230, 231) quotes Balch’s chemical 
analysis of the bulb of Pelagophycus Porra of the southern Cali- 
fornian coast, showing that 48 per cent. of its dry weight consists 
of potassium chloride. Dr. Е. К. Cameron (loc. cit. 42) states that 
Nereocystis Luetkeana, which is the principal kelp of the Puget 
Sound region and occurs in abundance also farther south, has an 
average content of potassium chloride amounting to 30-35 per 
cent. of its dry weight, while Macrocystis pyrifera, which probably 
excels all the other kelps of the Pacific coast in the collective bulk 
of its growth, is about equally rich in this valuable compound. 
Dr. Coker’s notes, specimens, and photographs (see PLATE 18, 
FIGURE A) indicate that Macrocystis and other large seaweeds 
(Lessonia and Eisenia) are abundant on certain parts of the coast 
of Peru, and it is possible that these seaweeds will sometime prove 
important as a source of “potash” and will thus supplement the 
nitrogenous guanos which have brought large revenues to Peru 
Ж Senate Document No. 190, 62d Congress. 1012. 
