8g8 



THE TROPICAL AGRICULTURIST. 



[June i, 1885. 



the best. Mr. Mincliiu's letter published the other 

 day shows how limited the number is of plants from 

 which fibre can be profitrbly extracted by means of 

 machinery. We do not know that the list may not 

 be confined to the green aloe (Fourcoya gigantea), 

 the Moorwa [Sanscuiira Zcylanica), and the rhea 

 grass or ramie. — En.] 



HINTS ON TEA-MAKING IMPLEMENTS AND 

 MACHINERY. 



Si R] — One of the important processes of tea-making is 

 the withering. It is of no little consequence, that 

 this process should be somewhat under control, so 

 that it may arrive at completion at a convenient 

 hour, not too late, nor too soon. It is inconvenient 

 to have all ihe machinery waiting for the wither- 

 in" and not quite consonant with either convenience 

 or comfort, that a planter had to get up at one, two, 

 or three in the morning to call his coolies to work, 

 to suit the withering. This process is one, that 

 may be well under control, where a planter has 

 got tea-drier-heated air, or other heated air 

 at command. The- quickness of the process de- 

 pends on the dryness of the air. Not merely on the 

 temperation, though that has something to do with 

 it ; the dryness of the air is the cnief thing. With 

 a clerihew arrangement and fan, the speed of the 

 fan could be regulated to regulate the withering. Or, 

 by turning on the heated air from the tea drier, the 

 process might be expedited, and by turning it off, and 

 if need be saturating the air with a chiuchoua waterer 

 or other spray producer the process could be delayed. 



But to do any of these with any thing approach- 

 ing to accuracy some implement to measure the dryness 

 of the air must be used. Mere temperature is no 

 measure of dryness. Air at <S0 o may be very dry, 

 while air at 100° may be at the point of saturation. 

 Some hygrometer must therefore be used to test the 

 dryness of the air used for withering the leaf, Per- 

 haps no simpler or better can be got than the wet mid 

 dry bulti thermometer. These can easily be procured 

 at any shop, or one can easily be constructed by 

 using two thermometors, that are fairly accurate. 

 Wrap a piece of rag round tbo bulb of one, and keep 



(1 ther end of the rag in water, iu a small cup 



fined to the thermometer, and kept full of water. As 

 the air when dry allows of rapid evaporation from 

 the rag on the bulb and this evaporation cools the 

 bulb of the thermometer, the mercury in the wet hull) 

 tube descends, to that the difference of the reading 

 of the two thermometers shows the dryness of the 

 air. Some calculations are needed for great accuracy, 

 but for withering purposes the observation of the 

 difference will probably be enough. In this variable 

 climate the differences may be from 2' to '.'0°. At 

 2° the withering would be at a staudstill, at 20° dif- 

 ference it would be rapid indeed. A few experi- 

 ments with such an instrument, and comparison of 

 its indications with the withering of the leaf, would 

 enable the planter to have a pretty accurate i 

 blow to regulate his withering. 



After withering comes rolling, ergo something inns', 

 bo said about rollers. Of these there are numbers 

 of competing machines. Perhaps the " Excelsior ' aud 

 the " Universal " are considered the thing by most plan- 

 ters. Tbey rollwcdl but have very serious defects. They 

 are wrought by a' very peculiar crank, which wastes 

 power prodigiously. This crank is ingeniously contrived 

 so as to produce a perfectly circular motion, i. 8, auy 

 point on the box describes a perfect circle on the bot- 

 tom. This result is obtained at an enormous waste 

 of power in working the peculiar crank. To estimate 

 this we may regard the crank, that works the bar 

 and bottom as a lever with the power applied at the 

 middle of it. The box moves in a straight line only 



and the bottom moves in a straight line at right angles 

 to the box. As the cog-wheel revolves dragging on 

 with it the crank, there are four points in the re- 

 volution, where the power is working perpendicular 

 to the lever, and consequently the power applied acts 

 alike at both ends of the lever each end having the 

 half, i. e. if the power be eight horse-power each end 

 of the lever is moved by four horse power. One end is 

 free to move in the direction of the power, the other 

 not at all, so half the power applied is wasted at 

 those four points of the revolutions. At other four 

 points, where the power acts in the direction of the 

 crank, the power actually in use is about five-eighths 

 of that applied, and between these points it varies 

 from (3 to |) a half to five-eighths of the power 

 applied. But this is by no means all the waste. The 

 power working the box is applied at one side, and 

 the guiding slides are at the other, involving some- 

 thing like a three-eighths waste of power there also. 

 And this wasted power is not simply got rid of, it 

 goes to increase friction, which consumes more power 

 iu overcoming it. Again the workiug of the crank 

 has been in this way calculated on the supposition, that 

 box and bottom need equal power. Probably how- 

 ever from its greater weight, and the side thrust 

 of the power applied to moved the box, it needs 

 twice the power needed for the bottom. Consequently 

 there will be two points of .each revolution, where 

 a great accession of power is needed, and 

 two where it is at a minimum thus requir- 

 ing a fly-wheel of considerable size to get uni- 

 formity of action. Taking all things into consider- 

 ation, it would perhaps be no exaggeration to say, 

 that, on account of this peculiar crank, out of eight 

 horsepower applied to drive the machines somewhere 

 about three horsepower is actually effective in the 

 work, for which the machine is devised. This comes 

 to be a very serious question for a planter, who has 

 got a waterwheel fitted for producing three or four 

 horsepower, while an excelsior may need eight. It 

 means a new wheel or a steam-engine or a turbine, 

 as the case may be. And when we come to con- 

 sider further, it appears that the advantages of the 

 use of this crank are merely theoretical, but of no 

 practical value. It may be that a perfect circle is 

 more beatiful than an imperfect figure. But tea, at 

 least, Ceylon tta does not seem to be over-fastidious 

 on that point. Kerr's and Jackson's band-roller that 

 effect an ovate or other deviation from the circle pro- 

 duce as satisfactory a roll. Auother crank could easily 

 be applied, produciuga sufficiently good approximation 

 to the circular motion, and not liable to the charge of 

 such a great waste of power. I have gone at length into 

 this point, as it is a matter involving very serious 

 considerations in the economical working of tea estates. 

 Kerr's machines are generally allowed to do good 

 work, but complaints are made of the gallows, and 

 of the brush action arrangements getting out of 

 order. \Vhy does not Kerr enlarge bis machine and 

 do away with the gallows and perfect his brush action, 

 ;c favourably with either Universal 

 or Excelsior? The saving in power and in prime cost 

 is all iu his favour. I suppose there are other good 

 machines which I have not seen. However, the 

 machines of the future, which is to supersede all 

 others, must be a continuous acting one, taking in 

 tea at one end and giving out roll at the other. In- 

 ventors set your wits to work on this desideratum ! 

 Some I believe are busy planuing. By aud bye Ceylon 

 ingenuity will be to the front. 



After rolling aud fermenting comes drying. So we 

 must have a word about driers. The preponderance 

 of votes seems to favour the No. 3 Sirocco. It seems 

 to have many advantages over others. But there 

 seems also a considerable defect in it. All 

 experiments in drying seem to point to the ad- 



