62 BULLETIN 150, U. S. DEPARTMENT OF AGRICULTURE. 
doubted if the fertilizers of which they form a part were used in 
very great amount. They are objectionable on the further score 
that they render the material of which they form a part hygro- 
scopic, which property in moist air causes the fertilizer to cake. 
The ingredients of kelp other than potassic, it has been shown, are 
salt and organic matter, the nitrogen of which, rated as ammonia, 
adds materially to the market price of the product. The organic 
matter itself is of value, as contributing — to a small extent, to be 
sure — to the organic constituents of the soil, known by the indefinite 
term of "humus." 
PREPARATION OF DRY FERTILIZER FROM KELP. 
Since the ingredients of kelp are either neutral or beneficial in their 
influence on plant growth, to prepare kelp for use as a fertilizer it 
is necessary only to convert it into a form in which it can be pre- 
served and shipped. To accomplish this it is sufficient to harvest, 
drive off the water which it contains, and grind it to a coarse powder 
for bagging and mixing. 
Kelp is being harvested by a machine which embodies the prin- 
ciples of the mowing machine or reaper used in harvesting agricul- 
tural products. The harvester actually in operation consists 
essentially of a barge over the end of which projects an adjustable 
frame, supporting an endless belt, tilted to form an inclined plane. 
Across the lower end of the belt extends a horizontal cutting bar 
about 10 feet in length, of the type used in the construction of reapers, 
which is supplemented at each end by two perpendicular knives. By 
this arrangement a swath may be cut through the kelp 10 feet in 
width and of a depth determined by the adjustment of the supporting 
frame. Back of the knives the belt, constructed of chains and 
netting, is operated in such a way as to catch the severed kelp and 
lift it upon the barge. Beneath the upper end of the belt is a 
chopper into which the kelp drops and by which it is cut into short 
lengths. From this it passes onto a short conveyor which loads it 
into a large scow made fast alongside. The small barge carrying 
the cutter is moved along the side of the large scoav so that the load 
of cut kelp is distributed evenly. To operate the moving parts of 
the machine a gasoline engine is provided. The barge and scow 
are pushed through the kelp groves by a launch, which serves also 
to tow them to the dock for unloading. (PL VI, fig. 2.) 
The cost of cutting will be determined by the conditions obtaining 
at the place of cutting. The results obtained so far indicate that this 
will be not more than 50 cents per raw ton, and easily may be reduced 
to 25 cents or less, inclusive of unloading at the dock. 
It can not be expected that the cutter now in operation embodies 
all the perfections to which such a machine is susceptible, nor that 
