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 circumference, 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.
[Illustration: A [V]-CUT ON HALF THE CIRCUMFERENCE.]
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 quantity 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:
(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.