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THE NAVAL STORES INDUSTRY. 
25 
Table 14. — Summary of total yields for four years based on the dip and scrape being 
corrected to the same number of chipping s per crop (8 ,000 > faces) . 
Dip. 
Scrape. 
Crop. 
Yield. 
Increase. 
Yield. 
Increase. 
Decrease. 
A .. 
Pounds. 
206,235 
211,911 
214, 503 
279,260 
Per cent. 
Pounds. 
47, 742 
44, 838 
39, 775 
53,915 
Per cent. 
Per cent. 
B . 
2.75 
4.01 
35.41 
6.08 
c 
16.69 
D 
12.93 
Two crops, G and H, were worked for one year, combining the 
principles observed under crops B and C, namely, shallow and 
narrow chipping. Crop X was chipped in the ordinary way. Table 
15 gives the yields. 
Table 15. — Summary of yields for one year. Crops X, G, and H. 
Crop. 
Number 
of 
cups. 
Number 
of chip- 
pings. 
Yield 
of 
dip. 
Increase. 
X 
9,880 
9,880 
9,880 
35 
35 
35 
Pounds. 
90, 094 
124,292 
121, 474 
Per cent. 
G 
38 
H 
35 
As seen from Table 15 there is a decided increase in yield by the 
use of shallow and narrow chipping. 
EFFECT OF TURPENTINE OPERATIONS ON TIMBER. 
INJURY FROM FIRE. 
Since the box is rarely more than 12 inches from the ground, it 
is within easy reach of ground fires. As both box and face are 
saturated with resin, a fire once started in the box may burn the 
tree off at the base or render the face and box unfit to produce gum. 
In cupped timber the cups are moved up at the end of the season 
and are less exposed to fires. 
Another source of fire arises from the resin which impregnates 
the ground at the base of the tree. Such resin may come from 
losses in dipping, overflow from boxes on very productive trees, or 
from leaning trees. This waste resin may defeat the entire purpose 
of raking. Spilling is less likely to occur with cups than with boxes, 
since the former can be detached and held directly over the bucket 
in dipping. By having extra cups for very productive trees the 
chipper who visits them weekly can quickly change the full cups 
for empty ones and thus prevent overflow. 
88767°— Bull. 229—15 4 
