58 BULLETIN 150, U. S. DEPARTMENT OF AGRICULTURE. 



Table XI. — Chemical composition of Macrocystis. 



Location. 



K 2 0. 



I. 



N. 



Per cent. 



Per cent. 



0.23 



1.37 



.20 



1.81 



.15 



2.18 



.14 



1.00 



.24 



2.16 



.26 



2.32 



.18 



2.11 



.32 



1.83 



.14 



2.35 



.25 



2.72 



.24 



2.15 



.29 



1.54 



.32 



1.57 



.26 



.95 



.29 



.90 



.17 



1.00 



.20 



.98 



.38 



1.04 



.23 



.74 



.15 



.90 



.06 



1.08 



None. 



2.68 



Trace. 



2.69 



None. 



2.19 



.10 



1.25 



.30 



2.64 



.19 



1.83 



Organic 

 matter. 



Low Point, Wash 



Neah Bay, Wash 



Pillar Point, Cal 



Santa Cruz, Cal 



Monterey Bay, Cal 



Point Aulon, Cal 



Point San Luis, Cal 



Rocky Point, Cal 



Point Conception, Cal 



San Miguel Island 



Santa Cruz Island 



Anacapa Island 



Cape Quemada, Cal 



Goleta Point, Cal 



Point Las Pitos, Cal 



La Jolla Point, Cal 



Point Medanos, Cal 



Point Loma, Cal 



Between Duke Island and Bee Rocks, Alaska 



56° 21' N., 133° 36' W 



57° 13' N., 133° 34' W 



57° 01' N., 134° 34' W 



55° 22' N., 133° 16' W 



54° 58' N., 132° 29' W 



Average 



Per cent. 



12.80 



19.60 



f 17.26 



I 27.66 



16.44 



f 18 .30 



I 12.38 



23.00 



8.62 



9.35 



14.17 



16.40 



17.40 



12.60 



14.10 



16.70 



12.30 



13.60 



13.40 



15.70 



11.49 



8.63 



6.92 



7.30 



13.26 



22.48 



Per cent. 

 59.40 

 51.50 

 58.14 

 41.04 

 59.80 

 57.00 

 68.80 

 51.20 

 68.26 

 73.06 

 62.95 

 50.60 

 49.40 

 64.40 

 63.50 

 56.70 

 66.20 

 64.40 

 62.90 

 60.90 

 67.34 

 72.24 

 73.96 

 73.24 

 64.36 

 49.02 



13.63 



63.00 



In these tables the potash is recorded as such — that is, as the 

 oxide, the conventional manner of expressing the potassium con- 

 tent of fertilizers. It must not be understood that this is the form 

 in which it occurs in the plant. When the plant has been incin- 

 erated at low heat, so that all volatile organic matter has been 

 driven off and only charcoal remains, and leached, potassium chloride 

 is obtained. While it is not known definitely what compound of 

 potassium exists in the living plant, it may be regarded as potas- 

 sium chloride. In addition to the potassium chloride, sodium 

 chloride is present in varying amounts, roughly equal to about 

 one-third that of the potassium chloride. Also, there are small 

 quantities of phosphoric and sulphuric acids, calcium, and 

 magnesium. By lixiviation practically all of the soluble salts, 

 principally of potassium and sodium, are removed. If the remain- 

 ing charcoal then be burned, an ash remains which consists essen- 

 tially of calcium and magnesium carbonate and phosphate. The 

 percentage of ash varies from 3 to 12 per cent, the variations being 

 determined by the part of the plant undergoing analysis. The 

 stipe carries a much higher proportion of ash than the leaves or 

 fronds. 1 



1 For analyses of the various kelps of the Pacific coast other than and including those 

 of commercial importance, and for others of various alga? of various parts of the world 

 copied from the literature, see App. P of S. Doc. 190, Sixty-second Congress, second 

 session. 



