EDIBLE CANNA IN WAIMEA DISTRICT OF HAWAII 
39 
the long axis of the drum are attached at intervals between succes- 
sive threads of the worm. The rootstocks are fed into the drum 
which rotates partly under water; thence they are worked by means 
of the worm to the opposite end of the cylinder. The wooden cleats, 
which alternately lift and drop the rootstocks, facilitate the washing. 
The rootstocks are next run into the hopper of the grater. This 
consists of a sheet of perforated iron which has been fitted on a wooden 
cylindrical core 36 inches long and 24 inches in diameter to form the 
grater. It revolves about 300 times a minute. Water is copiously 
used in the grating process to facilitate shredding and to keep the 
grater clean. The pulp from the rasper is then led into a revolving 
cylinder the surface of which is covered with brass screening (60 
meshes to the inch). The cylinder is 9 feet long and 3 feet in diam- 
eter. Fully 90 per cent of the extraction is done by this machine. 
The pulp is sprayed with water and passed from the revolving screen 
Fig. 19.— Interior of a starch mill at Waimea, Hawaii 
to the first beater. This is a sheet-iron cylinder 2 feet in diameter and 
8 feet long having paddles which revolve at the rate of 240 times a 
minute attached to the shaft. The beater breaks the clumps of 
pulp and releases more starch. The pulp then is carried from the 
first beater to the first shaking screen (80 meshes to the inch). This 
screen is 4 feet wide, 10 feet long, and has a pitch of 6 inches. It is 
driven by means of an eccentric which works the pulp gradually 
down the surface. Water is again sprayed over the pulp as it passes 
down the screen to facilitate further the extracting of the starch and 
the pulp is then passed into a second set of beaters and screens. 
The starch water from the three screens is then combined and 
passed through a set of three shaking screens 2 by 6 feet each (80, 
100, and 120 meshes, respectively, to the inch) for the removal of 
fine particles of pulp. The starch water is then run into the flumes. 
These are 140 feet long, 18 inches deep, and 18 inches wide, and are 
set at a pitch of 6 inches to 140 feet. The starch settles in the 
