24 
BULLETIN 229, IT. S. DEPARTMENT OF AGRICTJLTUEE. 
Table 13. — Comparison of the amount of scrape formed by the cup and box systems, 
season 1902, Georgia. 
Half crop. 
Net weight Net weight 
of scrape. | of dip. 
Total 
weight of Percentage 
' ' gum ' ' dip of scrape, 
and scrape. 
First year: 
Boxes.., 
Cups.... 
Second year 
Boxes... 
Cups 
Third year: 
Boxes.., 
Cups 
Fourth year 
Boxes... 
Cups..., 
Pounds, j Pounds. 
10,315 42.787 
13,155 51,081 
17,120 
12,210 
8.5S0 
7. 200 
7,970 
6,635 
35,700 
42, 630 
15,435 
2S,245 
14.385 
25,305 
Pounds. Per cent. 
53,102 1Q.4 
64,237 20.5 
52,820 
54,840 
24,015 
35,445 
22.355 
31, 940 
32.4 
22.3 
35.' 
a.: 
35.6 
20.8 
Scrape is troublesome to collect, yields a low grade of resin, and 
gives but 11 per cent of turpentine on distillation, while gum col- 
lected by the cup system yields about 19 per cent of turpentine. 
RELATIVE YIELDS FROM DIFFERENT DEPTHS AND HEIGHTS OF 
CHIPPING. 
In the years 1905 to 1908 the Forest Service carried out experi- 
ments to determine the effect of the depth and height of chipping on 
the yield of resin. Four crops * were used in the experiment, desig- 
nated A, B, C, and D, respectively. 
Crop A, taken as the standard, was chipped in the ordinary way, 
the average depth of chipping being seven-tenths of an inch and the 
average height five-tenths of an inch. 
Crop B was used to test the effect of shallow chipping, the average 
depth being four-tenths of an inch. 
Crop C served to show the effect of narrow chipping, the average 
height being four-tenths of an inch. 2 
Crop D was turpentined with reference to the possibility of work- 
ing the turpentine a second time. The present method consists 
in exhausting the tree within four years. This crop was chipped 
in the same manner as crop A, but the miinmum diameter of the 
trees turpentined was limited to 10 inches, as compared to a mini- 
mum diameter of 6 inches in crop A; in addition the minimum diame- 
ter of the tree to bear two faces was raised from 13 inches in A to 
16 inches in crop D; no tree in crop D had more than two working 
faces. 
Table 14 shows the yields from the four crops A, B, C. and D. 
i Crops of 8,000 faces each were used. 
2 It was intended to have the height of chip in 
the chippers cut wider than was desired. 
: C" half that in "A," but in spite of close supervision 
