into the new clearings as

( 47 ) stumps."

The

Planting is carried out at varying distances, but 24 feet by 12 feet is a favourite of many growers, as this allows of ample plants for thinning from the third year. tree grows to a height of 30 to 40 feet and develops a heavy foliage. Much of the old rubber was originally planted too close. Wider planting is now adopted, the general practice being Thinning. to plant about 120 trees to the acre, so that they may be eventually thinned to about 80 trees per acre. has been necessary to reduce the number of trees per acre. process of thinning is carried out gradually, all weakly or diseased trees being first removed, and later those which give poor yields. The result of thinning has been better average yields and a much better bark renewal.

It

This

The best time for cultivation is considered to be just before the wintering commences. Cattle manures, green manures, Cultivation. and artificial manures are all used. The approximate quantity of artificial manure used per annum per acre is up to 600 lb. Many estates, however, are now beginning to reduce the quantities of artificial manures applied to rubber, and forking is becoming more general.

Tapping.

Various systems of tapping are still in vogue. In the early days of the rubber industry a large number of cuts were made upon the trees usually either in the form of full or half herring-bone. These systems were gradually given up for the V-cut, the inverted V, two cuts, or the single cut, and the single cut (half-spiral) is now becoming universal. The frequency of tapping has also varied as experience has been gained. Daily tapping was formerly most common, but alternate day tapping is now generally popular, while tapping every third day is adopted upon some estates. Better bark renewal results if the interval between tappings is extended, but some loss of bark occurs in three-day tapping. Tapping generally commences when the trees are six to seven years of age, and upon trees whose girth at 3 feet above the ground has reached approximately

24 inches.

Tapping
Seasons.

The tree is generally rested for one month, from about February 15 to March 15, and during this period tapping operations are suspended. The freest flow of latex occurs during the north-east monsoon, about 60 per cent. of the year's yield being generally obtained in the second half of the year. It may be noted that heavy rain interferes with the collection of the latex, as it is washed out of the cut. The collecting cup is also filled with water, and the latex overflows on to the ground. Various devices for minimizing this loss are on the market, but they are still either not wholly satisfactory or too expensive.

The manufacture of rubber into the form in which it is put on the wholesale market is done in factories on the estates. Manufacture. A considerable quantity and variety of machinery is used, and it is, in general, efficient and economical. The manufacture is standardized, and the difference between the prices of the various grades is generally not very large.

( 48 )

Rubber is manufactured in two distinct ways: into (1) smoked sheet or (2) crêpe. To obtain smoked sheet the latex is first Smoked Sheet. standardized by the addition of water, then panned or troughed for coagulation, each sheet weighing 1 to 1 lb. dry weight after smoking. The rate of coagulation varies with the amount of acetic acid used, slow coagulation making for resilience in the rubber and economy of acetic acid. The coagulated rubber is then kneaded by hand and rolled in a smooth roller to extract the water in it, and is then put through a machine, which marks a diamond pattern on it in order to prevent the sheets sticking together and to accelerate drying. It is then cured by being put to dry in smoke in a specially constructed smoke room. After further drying for a period of seven to ten days the smoked sheet is ready for export. The grades are: best ribbed smoked sheet; inferior quality smoked sheet; plain smoked sheet.

Crêpe is obtained in a different way. After coagulation the rubber

is rolled into strips and then macerated by being put Crêpe. through crêping machines, which make the rubber into lace-like filaments. These are dried in a hot-air drier, and the filaments are then rolled together into blanket crêpe. Crêpe is ready for export in 24 hours if the weather is not excessively damp. The grades are: best pale from pure latex; mottled crêpe from washings. In addition to smoked sheet and crêpe, "scrap " rubber is also

manufactured. Scrap includes the latex which has Scrap. not flowed into the collecting cups, but has coagulated naturally on the cut; the cup scrapings; and the latex-" earth-scrap "—which has overflowed on to the ground. is cleaned and made into scrap crêpe. The grades are : scrap crêpe from tree scrap; brown scrap crêpe inferior quality; black scrap crêpe from earth rubber.

This

The yield per acre varies considerably with the soil, age of the trees,

rainfall, planting, treatment, &c., but may be said to Yield, Costs, &c. range from 150 to 700 lb. per acre, 400 to 500 lb. per acre being considered a good all-round yield for an estate in full bearing. A very good tree over twelve years old will yield 10 lb. dry rubber per annum, while the average per tree in full bearing may be put at about 4 to 5 lb. per annum. The average selling price in 1919 was something over Re. 1, but in 1920 there was a continuous decline, and in December pale crêpe was selling at 48 cents per lb., ribbed sheet at 38, clean brown scrap crêpe 30, curly scrap 23, giving an average generally under the cost of production. The downward trend continued to the end of June, 1921, when crêpe and ribbed sheet were at 43 and 37 cents, respectively. From July to September prices remained steady at from 43 to 50 cents, crêpe and ribbed sheet being at about the same level. The last three months of the year witnessed a considerable improvement; prices reached 70 cents in December, and closed for the year at 63 to 65 cents. The all-round average annual shippers' buying prices in certain years were the following:— -1912, Rs. 2.73 per lb. ; 1913, Re. 1·92; 1914, Re. 1·42; 1915, Re. 1·65; 1916 Re. 1·79; 1917, Re. 1·49; 1919, Re. 1; 1920, 70 cents; 1921, 43 cents.