308 



The Supplement to the Tropical Agriculturist. 



be made out of a wooden stick 5 to 6 feet long, 

 curved at one end ; the curved end is introduced 

 between the roots, and, by pressure on the 

 other end and a few strong shakes, the yams are 

 lifted. A stone or the blade of a changkol is 

 laid below the fulcrum to prevent its sinking in 

 the earth. If pieces of roots are broken in the 

 lifting, they must be dug out with the changkol. 



Before the lifting, the stems are cut down and 

 dropped between the rows ; they will supply 

 cuttings for the next planting, and the leaves 

 are left to rot on the ground. Before loading 

 the yams on the carts which are to convey them 

 to the factory, the cooly shakes off the earth 

 adhering to them. 



Yield in Yams. 

 In the experiment referred to above, in 

 Jamaica, the weight of roots dug up per acre 

 was also given, as follows, in tons : — 



Variety No. 1 .. 13'3 



No. 2 .. 11-4 



No. 3 . . ll - 4 



No. 4 . . 11-4 



No. 5 .. 11-3 



Leaving aside experimental results, which 

 cannot be considered as normal, we shall content 

 ourselves with yields obtained in practice by 

 large known estates, notably in Java : they will 

 do to show that manioc cultivation is a hand- 

 somely paying proposition. In Java, 25 tons 

 of roots are obtained currently from one 

 hectare, which is equivalent to 10 tons per 

 acre. The same figure is given as normal by 

 Mr E Copeland, in the Philippines. Mr Moor- 

 house, Manager of the Diamond Jubilee Estate, 

 Malacca, puts at 150 piculs of yams the crop of 

 one acre (1 picul=133| pounds). Ten tons per 

 acre is also given as a Ceylon crop. But as we 

 are dealing more particularly with the Straits 

 Settlements and F.M.S., we shall be safe in 

 • adopting Mr Moorhouse's figure of 150 piculs as 

 the normal crop of one acre, under good manage- 

 ment and under fair average conditions of soil 

 and climate. 



Yield in Starch. 



The yield in flour depends upon several 

 factors — soil, climate, cultivation and method 

 of extraction. Hence the importance of a 

 well-equipped factory and up-to-date machi- 

 nery. With such a mill, 20 to 25 per cent, 

 of the weight of the roots is obtainable. As 

 much as 30 per cent, has been extracted, and 

 Mr Copeland considers this figure as obtainable 

 commercially in the Philippines, but from figures 

 collected from Ceylon, Johore and Malacca, and 

 which we have before us, we incline for the safer 

 figure of 20 per cent. It is on this figure we shall 

 base our estimates. 



Extraction of the Starch. 



To extract as much as possible of the starch, 

 and to obtain it clean and white, the estate must 

 have an abundant supply of clear, running water. 

 The factory must, therefore, be on or in close 

 proximity to a stream, and a dam established to 

 store the water for use when wanted. Where 

 possible, it may supply the water-power for 

 the factory. Extraction includes the following : 



(1) The weighing of the roots on arrival at the mill, so as 

 to make sure that the work of extraction is carried on 

 with completeness, and, also, where the work of the fields 

 is done on contract, to apportion each coolies' crop ; 



(2) Cutting off the tops of the yams and giving them a 

 first steeping to get rid of the greater portion of the dirt. 

 Crooked roots should be broken at the angles as they will 

 pass more readily through the washer ;J 



(3) Putting through the washer; 



(4) *Slicing, or grinding or rasping the roots to a finely 

 divided pulp ; 



(5) Separating the starch from the pulp ; 

 Exhausting the waste pulp by pressure ; 



(7) Settling in tanks and repeated washings and clean- 

 ings of the starch in fresh water ; 



(8) Draining and drying the flour in the sun or in .heated 

 pans ; 



(9) Manipulation of the flour into pearl or flake tapioca. 

 As will be seen, although simple enough, the 



extraction of the flour necessitates a good many 

 handlings, but it will be found that much may 

 be done, in most installations, to save labour, 

 either by mechanical transporters or by so coup- 

 ling the machines that the pulp passes by its 

 own weight from one to the next. 



A second method of treatment of the roots 

 should be here mentioned, as it appears 

 applicable where the supply of water is not 

 abundant. So far as we understand it, the' roots 

 are put in heaps, well wetted with water, and 

 left to undergo a beginning of fermentation, 

 for from 4 to 6 days, according to the tem- 

 perature, when the thick skin becomes easily 

 detachable with the hands, leaving the starchy 

 flesh white and clean, which can be passed 

 direct through the rasper or through rollers, 

 and the resulting pulp washed in the ordinary 

 way. According to Mr. de Kuiff, who adopts 

 this method, there is no loss either of quantity 

 or quality of the starch. As we have not seen 

 it in operation, we can say no more ; but it 

 is conceivable that, if the fermentation is 

 carried too far, a risk exists of a partial de- 

 composition of the starch granules and a begin- 

 ning of alcoholic transformation. If this can 

 be safely guarded against, and if the product 

 does not suffer, there appears to be much in this 

 method to recommend it. 



Machinery. 

 Description op Machinery. — Methods of 

 work and types of machinery differ in various 

 countries and from estate to estate, and, in 

 the following descriptions, the writer is only 

 giving what he considers to be a serviceable 

 equipment. More up-to-date machinery no 

 doubt exists, and if we had the privilege of peep- 

 ing at some of the great starch-making works of 

 Germany, we would probably know a good deal 

 more than we do; but, on the other hand, it must 

 be remembered that we are dealing with tapioca, 

 not as a staple crop, but as a catch crop. The 

 putting up of a very expensive plant might de- 

 feat the object of the rubber planter, which is 

 to get out of tapioca the wherewithal to feed and 

 stretch out his rubber estate to the tapping 

 stage. A plain, workable installation will, under 

 the circumstances, be considered a desideratum, 

 and that is what we here propose. After weigh- 

 ing, the yams may be peeled and then taken 

 direct to the washer, or put, as they are, to 

 steep in wide-meshed baskets of wire-netting 

 lying in a tank half full of water. Most of the 

 dirt is thus detached : the baskets are then 

 lifted from the tank by means of a pulley and 

 transported on rails to the washer, wherein the 

 roots fall through a hopper. 



The Washer. 

 The Washer is a cylindrical drum, the sides 

 of which are formed of perforated galvanised iron 

 sheets, detachable, and joined by means of bolts 

 to wooden laths, They can easily be replaced 



