June i, 1885.]* 



THE TROPICAL AGRICULTURIST. 



§73 



CEYLON PLANTING : SEEING THE TEA GROW : 



WITH A GLANCE AT CACAO, CARDAMOMS 



AND OTHGR "NEW PRODUCTS." 



(Continued from page S66.) 



THE BLACKMAN AIR PROPELLER FOR CACAO PREPAR. 

 ATION AND FOR TEA DRYING— TEA ROLLERS AND 

 DRIERS-INFRINGEMENTS OF PATENTS— THE SIROCCO 

 AND THE AMERICAN FRUIT EVAPORATOR— STEAM VS. 

 WATER POWER — SEMEAWATTE ESTATE— ROADS VS. 

 RIVERS— SANDBANKS IN THE KELANI— A DREDGER 

 NEEDED— A RAILWAY IN THE FUTURE— PRESENT NE- 

 CESSITIES—PLENTY OF SINHALESE LABOUR AVAILABLE 

 — DIFFERENCE BETWEEN TEA AND ITS PREDECESSORS— 

 ARECANUT CULTIVATION,— TEA ESTATES IN THE 

 KELANI VALLEY — THE MAGNIFICENT SCENERY OF THE 

 KELANI VALLEY— AWISAWELLA AND SITAWAKA— 

 DANGERS FROM FLOODS— PROSPECT OF BRIDGES— 

 RUWANWELLA IN 1814 AND 1S85-MOSS IN THE LOW- 

 COUNTRY AND ON THE HILLS— LIME AS A CURE FOR MOSS 

 —MANURE AND ITS RESULTS— TEA ON OLD AND WORN 

 COFFEE ESTATES— CTTLEA MANURE— EFFEC OF MANURE 

 ON TEA— TEA ON PATANAS— INDIGENOUS ASSAM AT HIGH 

 ALTITUDES— OLD TEA TREES IN DOLOSBAGE— ASSURED 

 SUCCESS OF TEA IN CEYLON. 



In my last series of notes, I promised to further 

 notice the Blaekman Air Propeller. I have mentioned 

 what I saw of its performances at KawudapelelU, and 

 certainly I could not help feeling that, even more 

 than for cacao curing, it would be useful in regulat- 

 ing the temperature of tea factories. For instance, 

 in moderating the tremendous heat, from which at 

 Dunedin I had to fly, generated by Kinmond's blast 

 drier, I was told that the coolies in attendance on 

 the machine, required sometimes to use cumblies to 

 Boak the perspiration from their bodies. Heat is an 

 excellent thing, but even of a good thing there may 

 be too much. Kinmond's roller seems to err in the 

 same direction as the drier, in generating too much 

 heat. On this account and that of leaving too much 

 leaf in a flat state, I heard that on two estates these 

 rollers were to be abandoned in favour of Jackson's, 

 which really seems to be as near perfection (ex- 

 cept as to price) as any machine can be. The 

 principle of Kinmond's roller is that of two discs 

 facing each other and revolving perpendicularly. In 

 Jackson's one part is superimposed on the other, and 

 the action of the human hand is vevy closely imit- 

 ated by the double action of table and box. I must 

 State, however, that Mr. Thomas of Oonoonagalla was 

 perfectly satistied with the working of Kinmond's 

 roller, stating that it only required to be carefully 

 attended to, in order to give satisfaction. While on 

 the subject of rollers, I may say that I saw in the 

 course of my travels a Thomson's Ohallengo Roller, 

 but that I heard nothing in favour of its " most 

 peculiar" principle. It is driers, however, and not 

 rollers which generate heat in a factory, and to moder- 

 ate this heat or to send currents of air, or diffused 

 air, hot or cold, through a manufacturing or wither- 

 ing house in damp or misty weather, the Blaekman 

 propeller would seem to be calculated to have a 

 good effect. From a pamphlet, copy of which Mr. 

 Ross favoured mo with, I may take a few extracts 

 indicating the nature and pretensions of the machine, 

 which can be set in operation by hand or water- 

 power as well as steam : in- fact, it is described as 



" a mecVianieal contrivance for moving any quantity 

 of air with a minimum of power." It is said to 

 be in operation for the purposes of removing heat 

 from engine and boiler rooms, &o, ; foul a'r from 



110 



breweries, &c. ; steam from paper-mills, &c. ; dust 

 from rag-rooms of paper-mills, &c. : moisture from 

 wool-driers, &c. ; smoke from workshops, &c. ; odour 

 of cooking from restaurants, &c. After showing the 

 importance of fresh air to human life and health, 

 the pamphlet proceeds : — 



It is, however, surprizing that so important a subject 

 should be so little understood, ami that' it should have 

 taken so long to learn that Air will not, any more than 

 anything else, move unless impelled, [or drawn] and that to 

 move it in any direction it is necessary to apply for* e 

 acting in that direction. How to do this is the problem 

 to be solved. 



It is stated that fans have acted imperfectly, and 

 that the Blaekman air propeller, of which an eu- 

 graviog is given, 



Is the result of continued and costly experiment. Tho 

 blades are so formeel, especially towards the periphi rv, 

 that all radial and counter flow of air is prevented ; the 

 air is attracted or drawn in towards the whole of tho 

 supply surface, about 40 per cent, entering around tho 

 periphery ami 60 per cent, ou the side, and all the air 

 thus operated on is impelled directly forward from tho 

 discharge side of the Propeller, almost without friction 

 or waste of power. 



The Propeller is so constructed that the whole of its 

 surface is made use of either for the entrance or exitcf 

 air. The feed or supply area is as it ought to be, much 

 larger than that for discharge. Tho form and position of 

 each blade are such as have been found by experience to 

 be best aelapted for producing a maximum result under 

 average circumstances. 



The Blaekman Air Propeller, therefore, moves very 

 large volumes of air in a continuous straight column with 

 comparatively little power, with a minimum of noise and 

 friction, and against such au amount of resistance or 

 " water-gauge," that it fulfils happily conditions most 

 desired in Mechanical Ventilation. 



It is very light, easily fixed, and can be placed in win- 

 dow, door, ceiling, side wall, floor, or any other convenient 

 position. Where used for exhausting, or where a max- 

 imum effect is desired, it should revolve in the space to 

 be ventilated, delivering the foul air to the outside immedi- 

 ately, or through a Sue or shaft. The best results, 

 in comparison with size and power required, are in practice 

 most conveniently obtained by a 48-inch propeller, which 

 presents a sectional surface of 12 square feet. Thcwbeel 

 being S inches deep, has a large feed surface, the dimen- 

 sions of which are, the depth of wheel (S inches) by i' ,; 

 circumference (12 feet), equal to 8 superficial fei t, and 

 this, added to the 12 feet at the side, gives '_'() feet of 

 feed surface, and 12 feet of delivery surface for a 1-feet 

 diameter propeller, which, when driven at 330 revolutions 

 per minute, will move lo.OOO cubic feetof air per minute, 

 requiring rather less than oue actual horse power. When 

 driven at 570 revolutions per minute it will move 30 000 

 cubic feet, or 1,800,000 per hour, requiring 2j horsepower. 

 That is what the patentees say for the machine, 

 and Mr. Roes spoke favourably of its performances, 

 of which he afforded us an example. After stat'ng, 

 what we know from the effect of punkahs to be 

 true, that an atmosphere which is tultry and op- 

 pressive may be rendered cool and refreshing by 

 merely setting it fta motion, the letterpress proceeds : — 

 Arrangement of openings. — For successful ventilation it 

 is necessary that there shoulel be free entrance from the 

 outer air, and free exit to it for all the air required : 

 communication with a closed space, though large, will not 

 serve the purpose. 



AYhere it is important to avoid draughts the openings 

 inward should be small, numerous, and distributed. 



In all cases the collective area of such openings should 

 be at least equal to that of a circle tho same diameter 

 as the Propeller used. 



Leading facts. — Before proceeding to provide for ventil- 

 ation it is necessary to take into account all the Facts of 

 each case, for example : Heated air rises to the ceiling, 

 and heavier impurities, such as carbonic aeid tras, remain 

 near the floor ; it is, therefore, desirable that the Sow ol 

 air caused by the fauj should cross throughout the space 



