THE TROPICAL AGRICULTURIST, 
590 
[March i, 1898 . 
'be sufficient room for them. On a tree of “2 ft. 
0 in. in girth, four vertical rows of cuts may he 
made without serious injury. 
As eacli cut is made the milk liowing from 
"the cut above it should be guided downwards to 
it along the bark by means of a twig, otherwise 
*the milk is liable to be wasted by dropping to 
‘the ground from projecting portions of the bark. 
“ The bulk of the milk, e.specially in large trees 
'br trees which have not been recently tapped, 
ultimately Hows into the cups at the base of the 
.tree. Those should be kept covered in such a 
;way as to prevent dust or other rubbish falling 
.into the milk. As soon as the milk ceases to How' 
into the cups these are removed to a warm jdace, 
and in a few hours a cake of solid rubber can 
,ibe removed from each, which should be kept in 
a dry place until it has become propeily dry all 
through. The remainder of the milk dries upon 
the tree in the form of long strings, which are 
stripped off and rolled into balls. The whole 
^ of the rubber when dry is now ready for market. 
"The most .suitable times of the day and of the 
year for tapping are still the subject of e.\periment. 
The most satisfactory results have on the whole 
been obtained by tapping in the drier jiarts of 
^ the two monsoons, i. c., from January to April 
* anil in August and September. The taiiping 
should be done on dry days, otherwise it is 
j difficult to }>revent dilution of the milk .and to 
I dry the rubber. 
“ The tappings may follow oneanothei at intervals 
^of a week for about four to eight weeks. The 
"second taii[iing gives a much larger yield than 
' tlie first, and the third and fourth ta|.ipings are 
' usually very productive. In a series of e.Njieri- 
ments ma<le during 1897 on trees of about 2 ft. 
"mean girth, the average yield per tree of the 
. successive weekly tappings was as follows : — 
; First week ... '73 Fourth week ... -80 
Second week ... 1'48 Fifth week ... -67 
^Third week ... '97 | Si.xth week ... -52 
Total ... 5T7 oz. 
YiiiLi). — The statements as to yield of rubber 
found in books of travel and popular articles are 
very unreliable, and e.xperiments are being made 
“to tO'it the whole question of yield. The late 
' Dr. Trimen commenced in 1888 to tap one of t:ie 
' original trees at Henaratgoda, then nearly twelve 
' years old and 504 in. in girth a yard from the 
ground. 
' It was tapped on seven days between January 
' 25 and Frbruary 15, yielding 17^ oz. of rubber, 
on six days between .July 20 and August 29, 
■yielding 7 oz., and on four days between December 
b and 20, yielding 4.| oz. ; a total of 1 lb. 12J oz. 
■ The same method was followed in alternate years, 
with results as shown below : — 
• 1888 -. 1 lb. 12f oz. 1 1894 ... 3 lb. 3 oz. 
• 1890 ... 2 lb. 10 oz. 1 1896 ... 3 lb. 0;joz. 
1892 ... 2 lb. 13 oz. I 
Total... 13 lb. 7 oz. 
The average yield of this tree from the twelfth 
* to the t vventy-lirst year is thus almost l.j lb. per 
anmirii. This result is very good, and if all the 
•trees of the same age yielded as mneh rubber, 
the success of the cultivation wamld be assured. 
It should, however, be noted that the girth of 
this tree in 1888 was laiger than the mean girth 
of the whole plantatiorij as mencioned above, in 
1897, and that therefore this yield, if the tree 
• tapped be accepted as a fair sample, represents 
rather the result to be expected after twenty 
‘"year.s, by which time the average girth of the 
trees should be equal to the girth of this one 
at the time its tapping was commenced. The 
trees in question are about 30 ft. apart, i.e., 
50 trees to the acre. These data thus indicate 
a yield of about 90 lb. of rubber per acre in the 
twentieth year, a result insufficient to make it 
worth the while of private planters to take up 
rubber cultivation. 
It seemed probable that better results might 
be obtained by tapping younger and smaller trees 
more closely ijlauted, and experiments were there- 
fore begun in 1896 on a youn.^er plantation of 
trees at Henaratgoda. The mean girth in J anuary, 
1897, taken at 5 ft. 6 in. from the ground, of 
225 of these trees was 2 ft. 44 in. The figures 
already given for the average weekly yields 
represent the mean results of the tajiping of 27 
trees of a mean girth of 1 ft. 104 in., six inches 
less than the mean girth of the whole plantation. 
From six consecutive weekly tappings of each, 
a Tiiean yield of 5-17 oz. per tree was obtained! 
This represents a yield of 97 lb. per acre of 
.300 trees (12 ft. ajiart). If the trees tapped had 
been of the same mean girth as the whole plan- 
tation, the yield wonld probably have been at 
the rate of about 120 lb. per acre. Further, only 
six tappings were made, and the trees, after a 
rest of a few months, would probably have stood 
three or four more tappings whose yield miCTht 
have been at the rate of 30 or 40 lb. j ter acre. 
No record, unfortunately, was kept of the date 
wiien this plantation was made. It Is probably 
twelve years old at least. The sandy soil at 
Henaratgoda is unfavourable for Para rubber, and 
in better soil the trees would probably reach this 
mean girth in ten years or even les.s. It would 
seem, therefore, that if this cultivation is taken 
up in favourable localities, a yield of about 120 
to 140 lb. of rubber per acre may be expected 
after the tenth year. This estimate is, however, 
liable to moditieation by the re.sults of experi- 
ments which are still in progre.ss. 
Cost of opening Plantation.s.— The follow- 
ing estimate of the first yearbs cost of opening 
a jdantation of 300 acres of forest land with 
rubber was jirepared by Mr. F. Lewis. Assistant 
Conservator of Forests, Colombo: — 
1 !. 
Felling and clearing at 1112 per acre ...3,600 
Lining, 10 ft. by 10 ft., at 112 per acre.. 600 
Holing, at 75 holes percooly at 40 cents 697 
Filling and planting and carrying jdants 
from their nursery to holes, 3oO per 
cooly at 40 cents ... .. ... 175 
Draining : 300 ft. of drains per acre at 1 
cent per foot run .. ... ... 900 
Lines for coolies: 1 shed of 10 rooms of 
12 ft. by 10 ft., mud walls, and batti- 
calla roof, at 1130 per room ... 300 
Hoads for inspection, 2 miles ... 160 
Plant nursery, including watering ... 150 
Weeding, at He. 1 per acre per month 3,600 
Cost of surveying lines round plantation, 
say .. ' ... ... ... 75 
Contingencies, such as special work, 
bridges over streams, or supplying 
vacancies, &c. ... .. ... 250 
Salary of assistant ... .. .. 1,000 
Tappal cooly.. ... .. .. 121 
Tools ... ... ... ... 300 
Total.. 11,927 
This represents an average of 1140 per acre. 
A return of 114,200 is estimated to be obtained 
