32 
BULLETIN 1422, U. S. DEPARTMENT OE AGRICULTURE 
Table 6. — Yields of rubber trees on an estrada on the Rio Ouro Preto, Matio Grosso, 
Brazil, tapped by the writer 
Tree No. 
First tapping 
(cubic centi- 
meter) 
Second tap- 
ping (cubic 
centimeter) 
Third tap- 
ping (cubic 
centimeter) 
Fourth tap- 
ping (cubic 
centimeter) 
Average of 
tappings (cu- 
bic centi- 
meter) 
Rub- 
ber 
yield 
(per 
cent) 
Cir- 
cum- 
fer- 
Latex 
Dry 
rubber 
Latex 
Dry 
rubber 
Latex 
Dry 
rubber 
Latex 
Dry 
rubber 
Latex 
Dry 
rubber 
tree 
(cm.) 
1 --. .. 
11.9 
25.6 
22.2 
1.9 
11.9 
23.3 
16.8 
24.8 
22.1 
9.6 
4.0 
22.3 
8.9 
23.0 
3.2 
89.9 
1.5 
3.1 
7.7 
53 
68 
46 
10 
28 
49 
45 
65 
83 
40 
13 
41 
10 
125 
54 
212 
5 
50 
35 
15 
40 
225 
84 
26 
43 
200 
172 
53 
17 
18 
27.9 
32.1 
23.4 
1.6 
20.6 
22.2 
19.6 
27.4 
39.3 
17.9 
7.3 
20.7 
14,5 
68.6 
26.4 
119.3 
4.1 
25.3 
16.6 
8.7 
12.5 
124.4 
42.9 
10.9 
10.5 
95.0 
72.2 
26.6 
19.6 
8.5 
55 
83 
36 
4 
52 
63 
47 
74 
63 
37 
41 
47 
38 
166 
45 
153 
33 
31 
31 
43 
245 
60 
28 
50 
169 
108 
64 
13 
18 
27.4 
37.9 
17. 1 
3.8 
20.6 
28.1 
20.4 
32.3 
29.9 
14.9 
17.2 
23.8 
16.4 
90.8 
19.2 
74.1 
4.0 
15.3 
14.6 
17.0 
13.0 
135.8 
29.1 
11.9 
18.7 
65.9 
37.5 
23.5 
11.6 
8.6 
55 
100 
54 
10 
46 
76 
48 
80 
82 
30 
49 
45 
40 
239 
50 
140 
8 
52 
35 
21 
37 
262 
70 
25 
53 
115 
96 
43 
12 
22 
23.7 
46.4 
27.5 
2.7 
18.2 
29.8 
21.0 
34.0 
40.8 
12.8 
18.2 
20.5 
13.9 
108.5 
21.7 
72.2 
"23.Y 
16.6 
11.1 
18.7 
138.1 
32.2 
~~42.~9~ 
17.4 
4.2 
9.6 
54.3 
102.0 
47.0 
8.5 
36.5 
61.2 
44.7 
71.2 
72.5 
34.5 
30.2 
47.2 
24.5 
164.0 
39.7 
174.5 
6.6 
36.7 
32.0 
22.3 
36.2 
243.0 
60.5 
25.0 
42.2 
137.2 
115.0 
45.2 
15.0 
17.7 
22.7 
35.5 
22.5 
25.0 
17.8 
25.8 
19.4 
29.6 
33.0 
13.8 
11.7 
21.8 
13.4 
72.7 
17.6 
88.9 
3.2 
16.9 
13.9 
12.3 
12.9 
133.6 
30.1 
10.2 
15.3 
80.5 
47.9 
18.7 
10.3 
8.0 
41 
34 
48 
29 
49 
42 
44 
42 
45 
44 
38 
46 
70 
69 
45 
50 
48 
46 
43 
55 
31 
55 
50 
41 
36 
56 
44 
41 
68 
45 
106 
2 
157 
52 
10 
20 
57 
39 
66 
62 
31 
18 
56 
10 
126 
10 
193 
173 
3 
134 
4 
116 
5 ... 
95 
6 - — --- 
129 
188 
8 
180 
9 
129 
10 ..: 
100 
11 
81 
12 
115 
13 
105 
14 
164 
15 
133 
16 - -. 
134 
17 - 
48 
18 . - 
12 
27 
122 
19 
124 
20 
73 
21 
25 
240 
28 
21 
23 
65 
84 
21 
18 
13 
7.5 
136.3 
16.0 
7.9 
21.2 
~~3&8~ 
7.1 
5.9 
5.1 
168 
22 
23 
24 
209 
180 
120 
25 
116 
26 
172 
27- . 
169 
28 
90 
29 
30 
120 
84 
These yields can not be compared directly with those in Table 1, 
because definite knowledge of the rubber content of the latex from 
that estrada is lacking. Samples of rubber coagulated from measured 
quantities were taken but lost in later travels. However, samples 
taken from the estrada at Porvenir, already mentioned, show that 
the rubber content of the latex there was 33 per cent. To assume that 
the latex from the three estradas from which data have already been 
given contains 33 per cent of dry rubber gives approximately the 
results shown in Table 7. 
Table 7. — Yields of rubber trees tapped by different methods 
Territory 
Tapping method 
Average 
daily 
yield of 
latex 
per tree 
(c. c) 
Average 
daily 
yield of 
dry 
rubber 
per tree 
(grams) 
Jebong knife on one-third circle 
Machadinho 
... do 
59 
93 
86.4 
64.6 
1 25. 1 
Do 
2 30. 1 
2 28. 5 
Do -.- 
do 
2 21.3 
1 
Samples weighed. 
2 Rubber content estimated at 33 per cent of latex. 
According to these data the Jebong knife gives, even in the first 
few days, yields that are comparable to those obtained by the macha- 
