58 BULLETIN 150, U. S. DEPARTMENT OF AGRICULTURE. 
Table XI. — Chemical composition of Macrocystis. 
Location. 
K 2 0. 
I. 
N. 
Per cent. 
Per cent. 
Percent. 
12.80 
0.23 
1.37 
19.60 
.20 
1.81 
( 17.26 
.15 
2.18 
[ 27.66 
.14 
1.00 
16.44 
.24 
2.16 
( 18.30 
.26 
2.32 
I 12.38 
.18 
2.11 
23.00 
.32 
1.83 
8.62 
.14 
2.35 
9.35 
.25 
2.72 
14.17 
.24 
2.15 
16.40 
.29 
1.54 
17.40 
.32 
1.57 
12.60 
.26 
.95 
14.10 
.29 
.90 
16.70 
.17 
1.00 
12.30 
.20 
.98 
13.60 
.38 
1.04 
13.40 
.23 
.74 
15.70 
.15 
.90 
11.49 
.06 
1.08 
8.63 
None. 
2.68 
6.92 
Trace. 
2.69 
7.30 
None. 
2.19 
13.26 
.10 
1.25 
22.48 
.30 
2.64 
13.63 
.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. 
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 
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 algae of various parts of the world 
copied from the literature, see App. P of S. Doc. 190, Sixty-second Congress, second 
session. 
