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1 May, 1899.] QUEENSLAND AGRICULTURAL JOURNAL. 337 
capable of dealing with, the growers turned their cattle into the field. Had 
the crop been held over, it might have been possible to get it in during the 
next season, and thus avoid a great deal of extra labour. 
To come back to the preparation of the bulbs for the mill: The stalks are 
first cut down with a handy implement such as a sharp hoe, cane knife, or 
reaping-hoox. The stool is then dug up with a strong mattock or astout-eyed 
No. 8 grubbing-hoe. A spade or fork is quite useless for the work, as the 
stool has a strong hold of the ground, in addition to which the bulbs of Canna 
edulis cling firmly together by the masses of rootlets proceeding from each 
bulb. The bulbs must be separated, and all earth adhering to them must be 
knocked off. As soon as dug, they must be carted to the mill; therefore it is 
well not to take up more than cau be operated on each day. Every day of 
exposure to the weather or to the hot sun has an injurious effect upon the colour: 
of the manufactured starch. . 
MACHINERY, 
The average return of a good crop will be about 30 ewt. of starch or ten — 
times the quantity in tons of bulbs. From 12 to 40 tons per acre have been 
dug from a field in which the plants were set at distances of 5 feet between the 
plants in rows 6 feet apart. 
It goes without saying that the -yield will vary according to Soil, locality, 
season, good or bad cultivation, and proper washing, grinding, and drying 
appliances ; but as a general rule the yield of starch may be set down at from 
15 ewt. to 80 cwt. per acre, although as much as 4 tons per acre of finished 
arrowroot has been obtained under exceptional circumstances. 
The machinery employed in the manufacture, in the very early days of 
agriculture in the colony, was as primitive as that used by the ancient Britons — 
for pounding grain, or by the Australian natives for crushing the seeds of 
Nardoo, with the differences that the small arrowroot grower made use of a 
grater made by punching holes with a nail in a piece of kerosine tin. Gradu- 
ally improvement crept in until a hand-machine was constructed by the writer 
which much accelerated the work, but was still only a makeshift. This. 
- machine is illustrated in the Journal (vol. I. p. 202). 
Since that date modern machinery has been introduced capable of turning 
out from 10 ewt. to 80 ewt. of arrowroot per day. abe 
In addition to a 6 horse-power engine, there are root-washers, grinding: 
mills, cylinders, sieves for separating the starch from the pulp, and centrifugals 
for drying. ‘To be more accurate, the requirements for an arrowroot mill 
capable of turning out 30 ewt. daily are: Engine of from 6 horse-power to 10: 
horse-power, carrier, rootwasher, elevator, grater or grinding mill, rotary 
sieves, shaker sieves (2), chute, patent circuitous trough (for which Mr. Lahey 
has obtained a patent) with agitators and sieves, centrifugal for draining,. 
tables and calico for drying.']} } 
The whole of the work, after the roots have been raised to the highest 
point of the building, is effected by gravitation. The roots, as they come 
from the field are tipped from the drays on to the carrier, whence they are: 
carried to the root-washing trough. Running through the centre of this is a 
spindle with pegs inserted diagonally into it, of sufficient length to ‘clear the. 
bottom and sides of the trough by aboutlinch. Here the bulbs are thoroughly 
cleansed of all dirt, stones, &e., and they are then passed on to the grater, a 
large wooden cylinder covered with perforated iron, burred, on to which the: 
bulbs drop from a hopper. A stream of water pours continuously upon this 
from above, and the pulp and starch held in suspension pass on to a shaking 
sieve. From this the farina and water pass to a second sieve, the pulp being 
ejected on the other side of the first sieve. On leaving this sieve, 
which is perforated with very fine holes, the water and farina are 
shot into a large trough, where the latter soon settles at the bottom. 
When a sufficient quantity »for the day’s work has passed into the 
trough, it is allowed to settle firmly, and the water is gradually drawn, ~ 
