The Preparation of Plantation Rubber Part 3

[Ill.u.s.tration: THE SINGLE CUT ON A QUARTER CIRc.u.mFERENCE, ON AN OLD TREE AND ON RENEWED BARK.]

In the s.e.m.e.nyih experiment the system chosen was that which had the greatest contemporary vogue--viz., two superimposed cuts on a quarter of the tree. The various blocks were tapped respectively every day, every second day, and every third day.

It was found that the conclusions drawn from the Ceylon experiment were not confirmed. After a period of three and a half years' continuous tapping neither the alternate-day system nor the third-day system gave results in any way approximating to the yield of the daily system.

The actual average yields from these systems over the whole period were in the order of--

_Daily._ _Two Days._ _Three Days._ 100 per cent. 60 per cent. 45 per cent.;

and throughout the course of the experiment neither of the other sections showed any appreciable improvement in position relative to the daily section.

In actual yields "per tapping" over the whole period the alternate-day and the third-day divisions showed advantages of 20 and 35 per cent.

respectively over the daily portion.

At the beginning of the second year of experiment another section of blocks was opened with a single cut on a quarter, tapped daily. This enabled direct comparison between the values of one cut and two cuts on a quarter in daily tappings and between a daily single cut and two cuts tapped alternate daily.

It appeared that the daily single cut yielded over the period of experiment 80 per cent. of that obtained by tapping two cuts daily; and that in the comparison between two cuts tapped alternate-daily and a single cut tapped daily the latter had an advantage of about 40 per cent. in yield.

This result has been used by advocates of daily tapping generally, but it does not const.i.tute a fair argument, inasmuch as the single cut was tapped twice as often, and its position was always relatively low on the hole of the tree. It has been shown in the comparison between the daily single cut and the two cuts daily that the influence on yields of the superimposed cut is relatively small. A fairer comparison would have been obtained if the two cuts tapped alternate-daily had been either amalgamated to form one long cut on half the tree or to form a [V] on half the tree, thus placing the cuts in the opposing sections on the same level. With the knowledge that the yield obtained from cuts is _always greater per tapping_ by using the alternate-daily system, it would appear to be plain that the one long cut on half the tree would at least equal the yield of the single short cut tapped daily on a quarter tree.

[Ill.u.s.tration: SINGLE CUT ON HALF CIRc.u.mFERENCE (HALF SPIRAL).

_Note._--In this particular instance the cut is changed to the opposite half of the tree every half-year.]

Unfortunately no opportunity has been afforded up to the present of definitely proving this point by prolonged experiment under strict conditions. It is true that the view is held strongly in some quarters as a result of the experience of managers, chiefly on their own estates, that alternate-daily tapping generally gives better yields than daily tapping.

In a number of instances this view is probably correct, and the writers are in agreement; but it is necessary to clear away some misconceptions which confuse the issue. In the main there are two schools, one of which plumps for alternate-daily tapping, while the other adheres strongly to daily excision. Great confusion exists, inasmuch as in many instances the disciples of these schools are really discussing different matters. In the case of managers who argue for alternate-daily tapping their experience is gained, with very few exceptions, from systems in which the excision covers half the circ.u.mference of the tree; whereas in almost all cases daily tapping is confined to a single cut on a quarter of the girth. Bearing on such a comparison there are, as far as the writers are aware, no reliable published experimental results. To compare the results obtained from one system practised on one estate with the results of the other system established on another estate is not strictly permissible, as we know that conditions generally may vary to an enormous degree.

The controversy has raged, however, to such an extent that many who are not directly engaged in estate practice have obtained confused impressions. For instance, it appears to be the belief in some quarters that alternate-daily tapping, when applied to a single cut on a quarter of the tree, will yield more than an exactly similar cut tapped daily. In support of such a statement there does not appear to be any confirmation under normal conditions; although such a result might be obtained in the case of old trees which have been heavily over-tapped in the past, and on which the rate of bark renewal has been appreciably r.e.t.a.r.ded. It might also be the case eventually when trees with the opposing frequencies have been tapped for a period extending into many years; but it is the opinion of the writers that under normal conditions such a result would be extremely doubtful.

When we come, however, to a comparison of daily tapping on a single cut on a quarter with double the length of that cut on half the circ.u.mference, at the same height, tapped alternate-daily--whether in the form of one long cut or in the form of a [V]--we arrive at a contrast which gives a clear issue. As already stated, facts and figures of reliable experiment are wanting; but it is the opinion and experience of the writers that the alternate-daily system at least suffers no disadvantage on the point of yields, and in other respects, such as conservation of labour and costs, is superior to the daily system.

[Ill.u.s.tration: A [V]-CUT ON HALF THE CIRc.u.mFERENCE.]

CHAPTER V

_TAPPING AND COLLECTING_

TAPPING KNIVES.--The choice of a tapping knife is a subject upon which there is much divergence of opinion. This must be so because no known knife has such apparent outstanding superior features or claims as would enable one to settle the point. Moreover, the personal factor is so large that, as far as the knives in common use are concerned, it appears to exert the greatest influence. The possibility of obtaining the ideal knife, which will go to sufficient depth into barks of varying thickness to yield the maximum quant.i.ty of latex without wounding, is quite as remote at the present time as it was some years ago. Meanwhile the search for that ideal knife continues, and occasionally one learns of the alleged merits of some new instrument which, it is said, fulfils all requirements. It is only to be regretted, both for the sake of the inventor and for the expectant buyers, that the claims always fail in some one or more particulars.

In Malaya probably the number of different types of tapping knives may amount to a half-dozen, but those most commonly in use are:

(1) The gouge--straight or bent.

(2) The ordinary farrier's knife.

(3) Modifications of the farrier's knife, such as the "Jebong."

Argument on the respective merits of knives is popular, and discussion seems endless. It is claimed for the bent gouge that it is superior to the straight instrument, because, the leverage being downwards on the handle, the tendency is to lift the cutting edge upwards and out of the bark, whereas with a straight gouge the tendency is to push the knife downwards into the bark. It is claimed, therefore, that the average shavings taken off by the bent gouge should be thinner than those obtained by the use of the straight instrument.

For similar reasons it is a.s.serted that the "Jebong" and other modifications are superior to the original form of the farrier's knife.

These points are generally accepted without great argument, but when comparisons are made between the gouge and the farrier's knife (with its modifications) the opinions of planters are so varied and conflicting as to be almost irreconcilable. Two opinions based on experience with both types of knives are often wholly contradictory.

There can be no doubt that the likes and dislikes of operative coolies have a considerable influence in determining the measure of success obtained with any one knife. Should coolies have been accustomed to the use of a particular form of instrument they become quite expert, and any proposed change creates in the minds of coolies a prejudice which is considerable in effect on the quality of the handicraft. Such prejudice may be overcome in course of time, but in the interval not a little damage may have been done in the shape of tapping wounds. So considerable is this question of personal favour that even on estates where a standard pattern of knife is issued coolies often modify that knife slightly on their own accord. Such alteration is ignored by the superintendents as long as the quality of the tapper's work is maintained at a high standard.

Naturally there is a limit to such leniency, and this limit is soon reached in the case of knives having adjustable parts controlled by screws, or nuts and bolts, etc. Some knives of this description really merit a much wider use than is afforded them at present; but in view of the potential damage which might be done as a result of adjustments made by the coolies these knives do not become popular.

It is not proposed here to enter into a description of even recent instruments for which strong claims are being made by their inventors or vendors. If they possess the merits attributed to them they will soon find favour, as managers are always keen on studying the points of any new knife which will lead to a conservation of bark and a reduction in the number of wounds. On the whole, it may be advanced that the best general results are obtained by the adoption of a simple non-adjustable knife and the retention of its use.

THE CHOICE OF LATEX CUPS.--It has come to be recognised that the maximum possible cleanliness is essential in all details of estate work, and the younger generation of planters could scarcely be aware that a few years ago it was deemed sufficient to use coco-nut sh.e.l.ls for the reception of latex on individual trees.

Terne-plate cups ousted the coco-nut sh.e.l.l, and they had the merit of being cheap. The interior coating of tin did not last long if the cups were properly cleaned. The iron being exposed, with a minutely roughened surface, each microscopic projection served as a point around which latex coagulated. Sc.r.a.pping the film of interior rubber became more and more difficult, and often the cups were burnt in order to get rid of the acc.u.mulation of rubber. The last state of such cups was worse than the preceding one. On some estates fairly successful attempts were made to keep these cups clean by making the coolies bring them into the store each day.

Terne-plate cups are not now in common use.

Aluminium cups have their advocates, but much the same argument applies to the difficulty of keeping them clean as was used in the foregoing paragraph. On many estates, however, they are used with success, the usual method of treatment being to make the coolies bring them into the store and clean them there. Owing to the comparative lightness of the material such a scheme is more feasible than was the case with terne-plate cups.

The cups now most in general use are either of gla.s.s or white-ware, and probably those of gla.s.s are the most extensively employed. There are many details to be studied in the choice between these two types of cups--_e.g._, percentage of breakage in transport and in the field, price when breakage is taken into account, etc.; but these apart the gla.s.s cups have one advantage--namely, the ability of the superintendents to see whether the cups have been properly cleaned. In the case of white-ware cups this means an inspection and handling of individual cups, whereas in the case of gla.s.s the point is settled by visual examination at a comparative distance.

[Ill.u.s.tration: SINGLE CUT ON TWO-FIFTHS OF CIRc.u.mFERENCE.

The opening cut covers two-fifths. Subsequent cuts occupy one-fifth of circ.u.mference.]

Gla.s.s cups are made in two patterns, one having a flat bottom and the other a conical base. The latter is convenient for use when wire supports are employed, the cup fitting into a loop placed beneath the spout. Used on the ground its shape is an obvious disadvantage, as, unless a hole is scooped for its reception, it has to be propped up with sticks or stones. Often a touch is sufficient to upset the balance, and latex is lost.

The flat-bottomed cup, on the other hand, may be used with success equally on a wire support or on the ground. It is sometimes said that owing to its shape the ease of cleaning, as compared with the half-spherical cup, is diminished, and that if the cups when not in use are kept inverted upon sticks placed near the foot of the tree the breakage is apt to be high.

This latter objection is being rapidly removed as the practice of using these sticks is losing vogue for various reasons, and wire cup-holders will be in general use as soon as the cost of material becomes normal.

There are on the market, and in fairly wide use, cups of Chinese and j.a.panese manufacture. These generally consist of brown earthenware with an interior gla.s.s finish. These are cheap in comparison with gla.s.s and white-ware cups, but it is a pity that the gla.s.s does not extend over the whole of the cup. The outer surface has a tendency to collect rubber and dirt. On some few estates small china bowls or saucers are still used and are quite satisfactory, except for the favour with which they are regarded by natives on the outskirts of the estates.

CLEANING CUPS.--The question of cup-cleaning would appear to be a very simple one; but in practice it is quite a source of worry to managers, especially where a mixed labour force is employed. Tamil coolies can be made to clean their cups in the day's task and at odd times. Chinese coolies, more often than not, either refuse to give the necessary attention or else demand extra pay for the work.

The method of cup-cleaning employed more popularly within recent years was that of daily was.h.i.+ng. The tapper carried two buckets, one for receiving the latex and the other containing water. Pouring the latex in the bucket the coolie then added a little water to the cup and added these rinsings to the latex collected. The cup was next washed hastily in the bucket of water and replaced. By the time the coolie has emptied and washed some 200 cups (about half the task generally) the water has the consistency of dilute latex, and the wet cup when replaced becomes coated with a thin film of rubber. If the latex is always collected in one direction it will be clear that, while the cups at one end of the task are comparatively clean, those at the other end have the chance of being correspondingly dirty.

Controversy has raged respecting this question of cup-was.h.i.+ng, and many estates have abandoned it as a daily practice. Coolies have not to carry an extra bucket of water. The contents of the cups are poured into the latex-bucket, and the bulk of the latex film remaining is also removed by the aid of a finger. The cup is then replaced, a thin skin of rubber forming on the interior surface. As a general rule this is easily removed on the next occasion, except perhaps in dry weather. It is the custom on most estates employing this practice to have all cups receive special attention at regular intervals.

There are certain economic factors entering into the difference of opinion regarding the two broad methods employed. In some cases--_e.g._, on old areas--it would be practically impossible to follow the older method of daily cup-was.h.i.+ng, as the tappers have to employ two buckets for the collection of the latex. The employment of special coolies for cup-was.h.i.+ng would be necessitated, such as may be seen sometimes on estates working Chinese "squatter" labour--where the man taps, a child a.s.sists in collecting, and another child, or the mother, washes the cups. It may be pointed out that in such instances the helpers are not paid by the estate.

Their services merely mean a saving in time which is spent in the squatter's garden, and perhaps the permission to the tapper to work a larger number of trees than would be allotted ordinarily to a task.

Again, on some estates, the tappers, while not being required to carry a bucket of water for cup-was.h.i.+ng, are given an increased number of trees to tap. Furthermore, on hilly areas under tapping, it is often manifestly unfair to expect the tapper to be able to carry two buckets during collection, when the slope is such, as to make the manipulation of even one bucket a matter of difficulty.

It will be seen, therefore, that there is no clear issue for argument concerning the two methods, and that the point must be decided on the economic factors peculiar to each estate or district.

[Ill.u.s.tration: EFFECTS UPON RENEWED BARK OF PREVIOUS TAPPING.