and Magazine of the Ceylon Agricultural Society. 



300 



when worn by use. The drum, 10 to 12 feet long, 

 revolves slowly, receivirg its movement direct 

 from the motor. Water, brought from an adjoin- 

 ing cistern, by a pipe with spraying spouts, plays 

 constantly over and on the sides of the drum. 

 The washer is lying at a slope, and the roots 

 pass of themselves to the lower part of the drum, 

 whence they fall, clean and free of earthy 

 matter, into the same basket which brought 

 them. The basket, now full of clean roots, is 

 hoisted up by means of pulleys to a platform 

 some 15 feet above, where the roots are emptied 

 by tilting the basket. — A more thorough cleaning 

 might, perhaps, be obtained by the adoption of 

 a type of cleaner similar to that in use in 

 certain preserve factories at Home, and 

 wherein, on the axis of the drum and concentric 

 to it, a beater, with four paddles, is fixed. 

 The paddles run through the length of the 

 drum, slightly spirally, with a very long thread. 

 This beater is so geared that it revolves 15 

 times faster than the drum, and the paddles, 

 being provided at their extremity with a small 

 broom, the roots receive a brushing at each 

 revolution. At the same time, the helicoidal 

 contour of the beater causes the roots to ad- 

 vance automatically to the end of the drum. 

 The Grater. 

 The Grater. — From the platform on which 

 they were emptied the yams fall through a 

 hopper on to a grater, which consists of a 

 wooden roller with sharp short spikes, which 

 revolves before a concave surface also with 

 spikes, the whole supported by a wooden frame 

 closed on all sides, except in front, where 

 a trough or drawer receives the pulp as it falls 

 from the roller, a jet of water playing meanwhile 

 on the roller to carry away the pulp. It is well 

 to note here that the cells containing the 

 gi'anulos of tapioca are very small, and that upon 

 the complete breaking and tearing of these cells 

 depends the perfection of the extraction of the 

 flour. For that reason, we give our preference 

 to grating over crushing with rollers, because, 

 in our opinion, the disintegration is more com- 

 plete when combined, as will be seen below, 

 with strong pressure. 



A grater of the model we have just described 

 18 inches long and 8 inches in diameter, will 

 treat 6 to 8 tons of roots daily, but it may be 

 made of large dimensions for larger quantities. 

 The Sieve. 

 The Sieve or Starch Separator.— From the 

 Grate*-, the pulp is brought orfalls into a hopper 

 which leads it to the sieve or starch separator, 

 a hexagonal or octagonal cylinder 14 to 16 feet 

 long, covered with fine brass wire gauze, 

 and lying at a slope. This cylinder revolves 

 slowly and water is kept running on it. 

 The separation of the starch is thus effected, 

 the starch grains passing through the meshes 

 of the gauze into a tank below, while 

 the vegetable and fibrous waste is dis- 

 charged at the lower end of the cylinder, to be 

 further exhausted by being passed to a strong 

 press whence it comes out as cake for pig food 

 or manure. After the starch has subsided in the 

 tank for 24 hours, the water is drawn off by 

 means of a syphon, fresh water brought in, and 

 the starch beaten to a cream is conveyed by 

 gutters to the washing tubs 



Washing Tubs.— These tubs are made of stout 

 boards, 6 to 8 feet in diameter and^4 feet^high. 

 The starch is allowed to settle at the bottom, 

 the water drawn off by syphon, fresh water ad- 

 mitted, and the stuff is stirred and beaten again. 

 This process of alternating, settling and stirring 

 is repeated every day for 5 or 6 days, when, the 

 water being finally removed the starch remains 

 clean and white ; the top layers, more or less 

 discoloured, can be scraped off and put through 

 a further washing. As much water is used in 

 these operations, the floor should be concreted 

 and slightly sloping to allow the water to run oft' 

 quickly. 



Drying of the Starch. 

 The starch, cut up in blocks, is next taken to 

 be dried. When the climate allows it, this may 

 be done in the open, on cemented barbecues, cov- 

 ered with a moveable roof, on rails, which, by 

 means of a tackle, may be drawn out or in for the 

 night, or when rain threatens. But modern fac- 

 tories are, besides, equipped with sets of large tin 

 pans, slightly concave, which are heated below, 

 from a brick flue, with a wood fire. In other fac- 

 tories, steam-heated kilns are used, and. lastly 

 desiccators, where the drying is rapidly completed 



If tapioca flour is required, the starch is taken 

 from the cleaning vats to racks, to drain ; it is 

 there cut up, crumbled with the hands or wooden 

 rakes, and then brought to the pans where it is 

 kept stirred constantly, over a gentle fire for a 

 quarter-of-an-hour. Care must be taken that it 

 does not turn into paste, which would make it 

 worthless. It can then be submitted to stronger 

 heat, and the drying can be quickened either by 

 steam or in the desiccator. The flour is then 

 ready for packing. 



The forms of tapioca known as "pearl" tapioca 

 or "flake" tapioca are the result of a special mani- 

 pulation in which the Chinese are adept. 



Mr. Copeland's Phocess. 

 Mr. Copeland describes the process used on 

 some plantations, somewhat in the following 

 terms (we have not the exact text before us):— 



"The tapioca is produced by pressing, rolling 

 and shaking the starch, still wet, in small round 

 pellets, obtained by forcing them through a 

 sieve on to a piece of cloth, which is kept con- 

 stantly agitated. These pellets are then rolled, 

 or fall of their own weight, on to an iron plate 

 which also is kopt shaking, and heated to a 

 temperature of about 100 degrees centigrade. 

 The heat causes a partial conversion of the 

 starch into sugar, swells the pellets which take 

 a gelatinous aspect. The product is called 

 "pearl'' tapioca. If the pellets are only 1 milli- 

 metre to 1.5 in diameter, it is called seed tapioca; 

 if 3 millimetres, "medium pearl; 1 ' if 5 milli- 

 metres, "bullet pearl." 



"Flake tapioca is heated and changes its com- 

 position in the same way, without being pre- 

 viously put into pellet form." 



Use of the Waste.— As we have said, the 

 waste left after exhaustion of the starch can be 

 used as pig food or as manure. As a forage for 

 working cattle, horses or bullocks, its nutritive 

 value is doubtful, as it contains very little nitro- 

 genous matter (only 1*39 per cent.) according to 

 the analyses of Mr Bonaine of the Agronomic 



